20851512 has 64 divisors (see below), whose sum is σ = 59875200. Its totient is φ = 5984640.

The previous prime is 20851511. The next prime is 20851513. The reversal of 20851512 is 21515802.

It is an interprime number because it is at equal distance from previous prime (20851511) and next prime (20851513).

It is a super-2 number, since 2×20851512² = 869571105372288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20851511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2938 + ... + 7094.

It is an arithmetic number, because the mean of its divisors is an integer number (935550).

Almost surely, 2^20851512 is an apocalyptic number.

20851512 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20851512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29937600).

20851512 is an abundant number, since it is smaller than the sum of its proper divisors (39023688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20851512 is a wasteful number, since it uses less digits than its factorization.

20851512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4196 (or 4192 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 20851512 is about 4566.3455848194. The cubic root of 20851512 is about 275.2406136540.

The spelling of 20851512 in words is "twenty million, eight hundred fifty-one thousand, five hundred twelve".