997864920 has 384 divisors, whose sum is σ = 3714984000. Its totient is φ = 239376384.

The previous prime is 997864909. The next prime is 997864937. The reversal of 997864920 is 29468799.

It is a Cunningham number, because it is equal to 31589²-1.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6697006 + ... + 6697154.

Almost surely, 2^997864920 is an apocalyptic number.

997864920 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997864920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1857492000).

997864920 is an abundant number, since it is smaller than the sum of its proper divisors (2717119080).

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

997864920 is a wasteful number, since it uses less digits than its factorization.

997864920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241 (or 225 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The square root of 997864920 is about 31588.9999841717. Note that the first 4 decimals coincide. The cubic root of 997864920 is about 999.2877995576.

The spelling of 997864920 in words is "nine hundred ninety-seven million, eight hundred sixty-four thousand, nine hundred twenty".