21031497504 has 192 divisors, whose sum is σ = 65251630080. Its totient is φ = 6567505920.

The previous prime is 21031497497. The next prime is 21031497523. The reversal of 21031497504 is 40579413012.

21031497504 is a `hidden beast` number, since 2 + 1 + 0 + 3 + 149 + 7 + 504 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3272214 + ... + 3278634.

It is an arithmetic number, because the mean of its divisors is an integer number (339852240).

Almost surely, 2^21031497504 is an apocalyptic number.

21031497504 is a gapful number since it is divisible by the number (24) 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 21031497504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32625815040).

21031497504 is an abundant number, since it is smaller than the sum of its proper divisors (44220132576).

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

21031497504 is a wasteful number, since it uses less digits than its factorization.

21031497504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6680 (or 6666 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The spelling of 21031497504 in words is "twenty-one billion, thirty-one million, four hundred ninety-seven thousand, five hundred four".