997213491 has 16 divisors (see below), whose sum is σ = 1477888800. Its totient is φ = 664568064.

The previous prime is 997213471. The next prime is 997213493. The reversal of 997213491 is 194312799.

997213491 is a `hidden beast` number, since 99 + 72 + 1 + 3 + 491 = 666.

997213491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 997213491 - 2¹⁰ = 997212467 is a prime.

It is not an unprimeable number, because it can be changed into a prime (997213493) 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, 100255 + ... + 109751.

It is an arithmetic number, because the mean of its divisors is an integer number (92368050).

Almost surely, 2^997213491 is an apocalyptic number.

997213491 is a deficient number, since it is larger than the sum of its proper divisors (480675309).

997213491 is a wasteful number, since it uses less digits than its factorization.

997213491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13395 (or 13389 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 997213491 is about 31578.6872906396. The cubic root of 997213491 is about 999.0702995917.

The spelling of 997213491 in words is "nine hundred ninety-seven million, two hundred thirteen thousand, four hundred ninety-one".