21516164258 has 4 divisors (see below), whose sum is σ = 32274246390. Its totient is φ = 10758082128.

The previous prime is 21516164251. The next prime is 21516164273. The reversal of 21516164258 is 85246161512.

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 + 7845176329 = 116923^2 + 88573^2 .

It is not an unprimeable number, because it can be changed into a prime (21516164251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5379041063 + ... + 5379041066.

Almost surely, 2^21516164258 is an apocalyptic number.

21516164258 is a deficient number, since it is larger than the sum of its proper divisors (10758082132).

21516164258 is a wasteful number, since it uses less digits than its factorization.

21516164258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10758082131.

The product of its digits is 115200, while the sum is 41.

The spelling of 21516164258 in words is "twenty-one billion, five hundred sixteen million, one hundred sixty-four thousand, two hundred fifty-eight".