21138845290 has 36 divisors (see below), whose sum is σ = 39796101954. Its totient is φ = 8083860048.

The previous prime is 21138845263. The next prime is 21138845309. The reversal of 21138845290 is 9254883112.

It can be written as a sum of positive squares in only one way, i.e., 19024960761 + 2113884529 = 137931^2 + 45977^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10573711 + ... + 10575709.

Almost surely, 2^21138845290 is an apocalyptic number.

21138845290 is a deficient number, since it is larger than the sum of its proper divisors (18657256664).

21138845290 is an frugal number, since it uses more digits than its factorization.

21138845290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4051 (or 2029 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 43.

The spelling of 21138845290 in words is "twenty-one billion, one hundred thirty-eight million, eight hundred forty-five thousand, two hundred ninety".