21155833154 has 4 divisors (see below), whose sum is σ = 31733749734. Its totient is φ = 10577916576.

The previous prime is 21155833103. The next prime is 21155833177. The reversal of 21155833154 is 45133855112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13670987929 + 7484845225 = 116923^2 + 86515^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5288958287 + ... + 5288958290.

Almost surely, 2^21155833154 is an apocalyptic number.

21155833154 is a deficient number, since it is larger than the sum of its proper divisors (10577916580).

21155833154 is a wasteful number, since it uses less digits than its factorization.

21155833154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10577916579.

The product of its digits is 72000, while the sum is 38.

The spelling of 21155833154 in words is "twenty-one billion, one hundred fifty-five million, eight hundred thirty-three thousand, one hundred fifty-four".