21139235460 has 288 divisors, whose sum is σ = 77856979200. Its totient is φ = 4534963200.

The previous prime is 21139235413. The next prime is 21139235473. The reversal of 21139235460 is 6453293112.

21139235460 is a `hidden beast` number, since 21 + 1 + 3 + 92 + 3 + 546 + 0 = 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 pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2605410 + ... + 2613510.

Almost surely, 2^21139235460 is an apocalyptic number.

21139235460 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 21139235460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38928489600).

21139235460 is an abundant number, since it is smaller than the sum of its proper divisors (56717743740).

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

21139235460 is a wasteful number, since it uses less digits than its factorization.

21139235460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8251 (or 8246 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The spelling of 21139235460 in words is "twenty-one billion, one hundred thirty-nine million, two hundred thirty-five thousand, four hundred sixty".