997991010025 has 9 divisors (see below), whose sum is σ = 1237515046231. Its totient is φ = 798388812040.

The previous prime is 997991009921. The next prime is 997991010077. The reversal of 997991010025 is 520010199799.

It is a happy number.

The square root of 997991010025 is 998995.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 359276763609 + 638714246416 = 599397^2 + 799196^2 .

It is not a de Polignac number, because 997991010025 - 2²³ = 997982621417 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4895076 + ... + 5094874.

Almost surely, 2^997991010025 is an apocalyptic number.

997991010025 is the 998995-th square number.

997991010025 is the 499498-th centered octagonal number.

It is an amenable number.

997991010025 is a deficient number, since it is larger than the sum of its proper divisors (239524036206).

997991010025 is an frugal number, since it uses more digits than its factorization.

997991010025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399608 (or 199804 counting only the distinct ones).

The product of its (nonzero) digits is 459270, while the sum is 52.

The spelling of 997991010025 in words is "nine hundred ninety-seven billion, nine hundred ninety-one million, ten thousand, twenty-five".