997071621 has 64 divisors (see below), whose sum is σ = 1682903040. Its totient is φ = 511142400.

The previous prime is 997071617. The next prime is 997071629. The reversal of 997071621 is 126170799.

It is a happy number.

It is not a de Polignac number, because 997071621 - 2² = 997071617 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997071629) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1658721 + ... + 1659321.

It is an arithmetic number, because the mean of its divisors is an integer number (26295360).

Almost surely, 2^997071621 is an apocalyptic number.

997071621 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

997071621 is the 18231-st octagonal number.

It is an amenable number.

997071621 is a deficient number, since it is larger than the sum of its proper divisors (685831419).

997071621 is a wasteful number, since it uses less digits than its factorization.

997071621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786.

The product of its (nonzero) digits is 47628, while the sum is 42.

The square root of 997071621 is about 31576.4409172408. The cubic root of 997071621 is about 999.0229192909.

The spelling of 997071621 in words is "nine hundred ninety-seven million, seventy-one thousand, six hundred twenty-one".