20515920 has 80 divisors (see below), whose sum is σ = 64525632. Its totient is φ = 5391360.

The previous prime is 20515919. The next prime is 20515921. The reversal of 20515920 is 2951502.

It is an interprime number because it is at equal distance from previous prime (20515919) and next prime (20515921).

It is a tau number, because it is divible by the number of its divisors (80).

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 (20515921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16935 + ... + 18105.

Almost surely, 2^20515920 is an apocalyptic number.

20515920 is a gapful number since it is divisible by the number (20) 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 20515920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32262816).

20515920 is an abundant number, since it is smaller than the sum of its proper divisors (44009712).

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

20515920 is a wasteful number, since it uses less digits than its factorization.

20515920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1260 (or 1254 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 20515920 is about 4529.4502977735. The cubic root of 20515920 is about 273.7560120445.

The spelling of 20515920 in words is "twenty million, five hundred fifteen thousand, nine hundred twenty".