21158022794 has 4 divisors (see below), whose sum is σ = 31737034194. Its totient is φ = 10579011396.

The previous prime is 21158022737. The next prime is 21158022803. The reversal of 21158022794 is 49722085112.

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., 16297841569 + 4860181225 = 127663^2 + 69715^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5289505697 + ... + 5289505700.

Almost surely, 2^21158022794 is an apocalyptic number.

21158022794 is a deficient number, since it is larger than the sum of its proper divisors (10579011400).

21158022794 is a wasteful number, since it uses less digits than its factorization.

21158022794 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10579011399.

The product of its (nonzero) digits is 80640, while the sum is 41.

The spelling of 21158022794 in words is "twenty-one billion, one hundred fifty-eight million, twenty-two thousand, seven hundred ninety-four".