997637531 has 16 divisors (see below), whose sum is σ = 1102899840. Its totient is φ = 894862080.

The previous prime is 997637527. The next prime is 997637551. The reversal of 997637531 is 135736799.

It is a cyclic number.

It is not a de Polignac number, because 997637531 - 2² = 997637527 is a prime.

It is a super-2 number, since 2×997637531² = 1990561286519551922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 997637531.

It is not an unprimeable number, because it can be changed into a prime (997637551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 403160 + ... + 405626.

It is an arithmetic number, because the mean of its divisors is an integer number (68931240).

Almost surely, 2^997637531 is an apocalyptic number.

997637531 is a deficient number, since it is larger than the sum of its proper divisors (105262309).

997637531 is a wasteful number, since it uses less digits than its factorization.

997637531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2954.

The product of its digits is 1071630, while the sum is 50.

The square root of 997637531 is about 31585.4005990109. The cubic root of 997637531 is about 999.2118893782.

The spelling of 997637531 in words is "nine hundred ninety-seven million, six hundred thirty-seven thousand, five hundred thirty-one".