21008234520 has 1152 divisors, whose sum is σ = 92376936000. Its totient is φ = 4279661568.

The previous prime is 21008234519. The next prime is 21008234521. The reversal of 21008234520 is 2543280012.

21008234520 is a `hidden beast` number, since 2 + 100 + 8 + 2 + 34 + 520 = 666.

It is an interprime number because it is at equal distance from previous prime (21008234519) and next prime (21008234521).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21008234521) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 724421866 + ... + 724421894.

Almost surely, 2^21008234520 is an apocalyptic number.

21008234520 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 21008234520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46188468000).

21008234520 is an abundant number, since it is smaller than the sum of its proper divisors (71368701480).

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

21008234520 is a wasteful number, since it uses less digits than its factorization.

21008234520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The spelling of 21008234520 in words is "twenty-one billion, eight million, two hundred thirty-four thousand, five hundred twenty".