21115495994 has 4 divisors (see below), whose sum is σ = 31673243994. Its totient is φ = 10557747996.

The previous prime is 21115495987. The next prime is 21115496009. The reversal of 21115495994 is 49959451112.

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., 14090877025 + 7024618969 = 118705^2 + 83813^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5278873997 + ... + 5278874000.

Almost surely, 2^21115495994 is an apocalyptic number.

21115495994 is a deficient number, since it is larger than the sum of its proper divisors (10557748000).

21115495994 is a wasteful number, since it uses less digits than its factorization.

21115495994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10557747999.

The product of its digits is 583200, while the sum is 50.

The spelling of 21115495994 in words is "twenty-one billion, one hundred fifteen million, four hundred ninety-five thousand, nine hundred ninety-four".