997215990 has 16 divisors (see below), whose sum is σ = 2393318448. Its totient is φ = 265924256.

The previous prime is 997215977. The next prime is 997216019. The reversal of 997215990 is 99512799.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16620237 + ... + 16620296.

It is an arithmetic number, because the mean of its divisors is an integer number (149582403).

Almost surely, 2^997215990 is an apocalyptic number.

997215990 is an abundant number, since it is smaller than the sum of its proper divisors (1396102458).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

997215990 is a wasteful number, since it uses less digits than its factorization.

997215990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33240543.

The product of its (nonzero) digits is 459270, while the sum is 51.

The square root of 997215990 is about 31578.7268584406. The cubic root of 997215990 is about 999.0711341420.

The spelling of 997215990 in words is "nine hundred ninety-seven million, two hundred fifteen thousand, nine hundred ninety".