997651381 has 8 divisors (see below), whose sum is σ = 1041546240. Its totient is φ = 953799792.

The previous prime is 997651357. The next prime is 997651397. The reversal of 997651381 is 183156799.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 997651381 - 2⁷ = 997651253 is a prime.

It is a super-2 number, since 2×997651381² = 1990616556022414322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997651351) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41811 + ... + 61183.

It is an arithmetic number, because the mean of its divisors is an integer number (130193280).

Almost surely, 2^997651381 is an apocalyptic number.

997651381 is the 19977-th centered pentagonal number.

It is an amenable number.

997651381 is a deficient number, since it is larger than the sum of its proper divisors (43894859).

997651381 is a wasteful number, since it uses less digits than its factorization.

997651381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21635.

The product of its digits is 408240, while the sum is 49.

The square root of 997651381 is about 31585.6198451131. The cubic root of 997651381 is about 999.2165133089.

The spelling of 997651381 in words is "nine hundred ninety-seven million, six hundred fifty-one thousand, three hundred eighty-one".