997388640 has 336 divisors, whose sum is σ = 3748133088. Its totient is φ = 249827328.

The previous prime is 997388621. The next prime is 997388659. The reversal of 997388640 is 46883799.

It is an interprime number because it is at equal distance from previous prime (997388621) and next prime (997388659).

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 55 ways as a sum of consecutive naturals, for example, 1982629 + ... + 1983131.

It is an arithmetic number, because the mean of its divisors is an integer number (11155158).

Almost surely, 2^997388640 is an apocalyptic number.

997388640 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 997388640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1874066544).

997388640 is an abundant number, since it is smaller than the sum of its proper divisors (2750744448).

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

997388640 is a wasteful number, since it uses less digits than its factorization.

997388640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The square root of 997388640 is about 31581.4603842191. The cubic root of 997388640 is about 999.1287878765.

The spelling of 997388640 in words is "nine hundred ninety-seven million, three hundred eighty-eight thousand, six hundred forty".