21908919770 has 32 divisors (see below), whose sum is σ = 39750858000. Its totient is φ = 8693761536.

The previous prime is 21908919751. The next prime is 21908919793. The reversal of 21908919770 is 7791980912.

It can be written as a sum of positive squares in 8 ways, for example, as 10090403401 + 11818516369 = 100451^2 + 108713^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1226342 + ... + 1244078.

Almost surely, 2^21908919770 is an apocalyptic number.

21908919770 is a deficient number, since it is larger than the sum of its proper divisors (17841938230).

21908919770 is a wasteful number, since it uses less digits than its factorization.

21908919770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18722.

The product of its (nonzero) digits is 571536, while the sum is 53.

The spelling of 21908919770 in words is "twenty-one billion, nine hundred eight million, nine hundred nineteen thousand, seven hundred seventy".