21739399090 has 16 divisors (see below), whose sum is σ = 39276391320. Its totient is φ = 8663432320.

The previous prime is 21739399067. The next prime is 21739399091. The reversal of 21739399090 is 9099393712.

It can be written as a sum of positive squares in 4 ways, for example, as 6457247449 + 15282151641 = 80357^2 + 123621^2 .

It is not an unprimeable number, because it can be changed into a prime (21739399091) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 4038091 + ... + 4043470.

Almost surely, 2^21739399090 is an apocalyptic number.

21739399090 is a deficient number, since it is larger than the sum of its proper divisors (17536992230).

21739399090 is a wasteful number, since it uses less digits than its factorization.

21739399090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8081837.

The product of its (nonzero) digits is 826686, while the sum is 52.

The spelling of 21739399090 in words is "twenty-one billion, seven hundred thirty-nine million, three hundred ninety-nine thousand, ninety".