21474731520 has 360 divisors, whose sum is σ = 81759485808. Its totient is φ = 5205319680.

The previous prime is 21474731491. The next prime is 21474731521. The reversal of 21474731520 is 2513747412.

21474731520 is a `hidden beast` number, since 21 + 47 + 4 + 73 + 1 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-2 number, since 2×21474731520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21474731521) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2783989 + ... + 2791691.

Almost surely, 2^21474731520 is an apocalyptic number.

21474731520 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 21474731520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40879742904).

21474731520 is an abundant number, since it is smaller than the sum of its proper divisors (60284754288).

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

21474731520 is a wasteful number, since it uses less digits than its factorization.

21474731520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7754 (or 7724 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 36.

The spelling of 21474731520 in words is "twenty-one billion, four hundred seventy-four million, seven hundred thirty-one thousand, five hundred twenty".