997877720 has 128 divisors (see below), whose sum is σ = 2727820800. Its totient is φ = 320910336.

The previous prime is 997877719. The next prime is 997877729. The reversal of 997877720 is 27778799.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997877729) 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 31 ways as a sum of consecutive naturals, for example, 568364 + ... + 570116.

It is an arithmetic number, because the mean of its divisors is an integer number (21311100).

Almost surely, 2^997877720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997877720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1363910400).

997877720 is an abundant number, since it is smaller than the sum of its proper divisors (1729943080).

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

997877720 is a wasteful number, since it uses less digits than its factorization.

997877720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1897 (or 1893 counting only the distinct ones).

The product of its (nonzero) digits is 3111696, while the sum is 56.

The square root of 997877720 is about 31589.2025856937. The cubic root of 997877720 is about 999.2920722900.

The spelling of 997877720 in words is "nine hundred ninety-seven million, eight hundred seventy-seven thousand, seven hundred twenty".