21587229138 has 32 divisors (see below), whose sum is σ = 44005703616. Its totient is φ = 7058515968.

The previous prime is 21587229137. The next prime is 21587229143. The reversal of 21587229138 is 83192278512.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21587229133) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98356 + ... + 229887.

It is an arithmetic number, because the mean of its divisors is an integer number (1375178238).

Almost surely, 2^21587229138 is an apocalyptic number.

21587229138 is an abundant number, since it is smaller than the sum of its proper divisors (22418474478).

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

21587229138 is a wasteful number, since it uses less digits than its factorization.

21587229138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328458.

The product of its digits is 483840, while the sum is 48.

The spelling of 21587229138 in words is "twenty-one billion, five hundred eighty-seven million, two hundred twenty-nine thousand, one hundred thirty-eight".