997939918 has 16 divisors (see below), whose sum is σ = 1535604336. Its totient is φ = 486106560.

The previous prime is 997939853. The next prime is 997939919. The reversal of 997939918 is 819939799.

It is a self number, because there is not a number n which added to its sum of digits gives 997939918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997939919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51805 + ... + 68407.

It is an arithmetic number, because the mean of its divisors is an integer number (95975271).

Almost surely, 2^997939918 is an apocalyptic number.

997939918 is a deficient number, since it is larger than the sum of its proper divisors (537664418).

997939918 is a wasteful number, since it uses less digits than its factorization.

997939918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17379.

The product of its digits is 9920232, while the sum is 64.

The square root of 997939918 is about 31590.1870523110. The cubic root of 997939918 is about 999.3128339109.

The spelling of 997939918 in words is "nine hundred ninety-seven million, nine hundred thirty-nine thousand, nine hundred eighteen".