21194520 has 64 divisors (see below), whose sum is σ = 63936000. Its totient is φ = 5620608.

The previous prime is 21194513. The next prime is 21194527. The reversal of 21194520 is 2549112.

It is an interprime number because it is at equal distance from previous prime (21194513) and next prime (21194527).

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 (21194527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28311 + ... + 29049.

It is an arithmetic number, because the mean of its divisors is an integer number (999000).

Almost surely, 2^21194520 is an apocalyptic number.

21194520 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 21194520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31968000).

21194520 is an abundant number, since it is smaller than the sum of its proper divisors (42741480).

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

21194520 is a wasteful number, since it uses less digits than its factorization.

21194520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 992 (or 988 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 21194520 is about 4603.7506448547. The cubic root of 21194520 is about 276.7416515835.

The spelling of 21194520 in words is "twenty-one million, one hundred ninety-four thousand, five hundred twenty".