21131430504 has 128 divisors (see below), whose sum is σ = 56818298880. Its totient is φ = 6532697600.

The previous prime is 21131430449. The next prime is 21131430521. The reversal of 21131430504 is 40503413112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 3776749 + ... + 3782339.

It is an arithmetic number, because the mean of its divisors is an integer number (443892960).

Almost surely, 2^21131430504 is an apocalyptic number.

21131430504 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 21131430504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28409149440).

21131430504 is an abundant number, since it is smaller than the sum of its proper divisors (35686868376).

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

21131430504 is a wasteful number, since it uses less digits than its factorization.

21131430504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5831 (or 5827 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 21131430504 its reverse (40503413112), we get a palindrome (61634843616).

The spelling of 21131430504 in words is "twenty-one billion, one hundred thirty-one million, four hundred thirty thousand, five hundred four".