21891770996 has 12 divisors (see below), whose sum is σ = 38312242500. Its totient is φ = 10945416000.

The previous prime is 21891770981. The next prime is 21891771007. The reversal of 21891770996 is 69907719812.

It can be written as a sum of positive squares in 2 ways, for example, as 12692275600 + 9199495396 = 112660^2 + 95914^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 746 + ... + 209246.

It is an arithmetic number, because the mean of its divisors is an integer number (3192686875).

Almost surely, 2^21891770996 is an apocalyptic number.

It is an amenable number.

21891770996 is a deficient number, since it is larger than the sum of its proper divisors (16420471504).

21891770996 is a wasteful number, since it uses less digits than its factorization.

21891770996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234754 (or 234752 counting only the distinct ones).

The product of its (nonzero) digits is 3429216, while the sum is 59.

The spelling of 21891770996 in words is "twenty-one billion, eight hundred ninety-one million, seven hundred seventy thousand, nine hundred ninety-six".