997578957 has 4 divisors (see below), whose sum is σ = 1330105280. Its totient is φ = 665052636.

The previous prime is 997578949. The next prime is 997579003. The reversal of 997578957 is 759875799.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 997578957 - 2³ = 997578949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997578937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166263157 + ... + 166263162.

It is an arithmetic number, because the mean of its divisors is an integer number (332526320).

Almost surely, 2^997578957 is an apocalyptic number.

It is an amenable number.

997578957 is a deficient number, since it is larger than the sum of its proper divisors (332526323).

997578957 is a wasteful number, since it uses less digits than its factorization.

997578957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332526322.

The product of its digits is 50009400, while the sum is 66.

The square root of 997578957 is about 31584.4733532158. The cubic root of 997578957 is about 999.1923335171.

The spelling of 997578957 in words is "nine hundred ninety-seven million, five hundred seventy-eight thousand, nine hundred fifty-seven".