997861780 has 12 divisors (see below), whose sum is σ = 2095509780. Its totient is φ = 399144704.

The previous prime is 997861723. The next prime is 997861853. The reversal of 997861780 is 87168799.

It can be written as a sum of positive squares in 2 ways, for example, as 296459524 + 701402256 = 17218^2 + 26484^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24946525 + ... + 24946564.

It is an arithmetic number, because the mean of its divisors is an integer number (174625815).

Almost surely, 2^997861780 is an apocalyptic number.

It is an amenable number.

997861780 is an abundant number, since it is smaller than the sum of its proper divisors (1097648000).

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

997861780 is a wasteful number, since it uses less digits than its factorization.

997861780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49893098 (or 49893096 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 55.

The square root of 997861780 is about 31588.9502832874. The cubic root of 997861780 is about 999.2867513974.

The spelling of 997861780 in words is "nine hundred ninety-seven million, eight hundred sixty-one thousand, seven hundred eighty".