21085618138 has 32 divisors (see below), whose sum is σ = 35561433600. Its totient is φ = 9303693696.

The previous prime is 21085618111. The next prime is 21085618241. The reversal of 21085618138 is 83181658012.

It is a junction number, because it is equal to n+sod(n) for n = 21085618094 and 21085618103.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1240783 + ... + 1257661.

It is an arithmetic number, because the mean of its divisors is an integer number (1111294800).

Almost surely, 2^21085618138 is an apocalyptic number.

21085618138 is a deficient number, since it is larger than the sum of its proper divisors (14475815462).

21085618138 is a wasteful number, since it uses less digits than its factorization.

21085618138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19006.

The product of its (nonzero) digits is 92160, while the sum is 43.

The spelling of 21085618138 in words is "twenty-one billion, eighty-five million, six hundred eighteen thousand, one hundred thirty-eight".