215720138 has 8 divisors (see below), whose sum is σ = 332325732. Its totient is φ = 104944896.

The previous prime is 215720117. The next prime is 215720149. The reversal of 215720138 is 831027512.

215720138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 215414329 + 305809 = 14677^2 + 553^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 215720138.

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, 1457495 + ... + 1457642.

Almost surely, 2^215720138 is an apocalyptic number.

215720138 is a deficient number, since it is larger than the sum of its proper divisors (116605594).

215720138 is a wasteful number, since it uses less digits than its factorization.

215720138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2915176.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 215720138 is about 14687.4142720902. The cubic root of 215720138 is about 599.7407565227.

The spelling of 215720138 in words is "two hundred fifteen million, seven hundred twenty thousand, one hundred thirty-eight".