997191640 has 16 divisors (see below), whose sum is σ = 2243681280. Its totient is φ = 398876640.

The previous prime is 997191599. The next prime is 997191647. The reversal of 997191640 is 46191799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997191647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12464856 + ... + 12464935.

It is an arithmetic number, because the mean of its divisors is an integer number (140230080).

Almost surely, 2^997191640 is an apocalyptic number.

It is an amenable number.

997191640 is an abundant number, since it is smaller than the sum of its proper divisors (1246489640).

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

997191640 is a wasteful number, since it uses less digits than its factorization.

997191640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24929802 (or 24929798 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 997191640 is about 31578.3413117282. The cubic root of 997191640 is about 999.0630023095.

The spelling of 997191640 in words is "nine hundred ninety-seven million, one hundred ninety-one thousand, six hundred forty".