331765981 has 2 divisors, whose sum is σ = 331765982. Its totient is φ = 331765980.

The previous prime is 331765979. The next prime is 331766009. The reversal of 331765981 is 189567133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 267845956 + 63920025 = 16366^2 + 7995^2 .

It is a cyclic number.

It is not a de Polignac number, because 331765981 - 2¹ = 331765979 is a prime.

It is a super-2 number, since 2×331765981² = 220137332297784722, which contains 22 as substring.

Together with 331765979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (331763981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165882990 + 165882991.

It is an arithmetic number, because the mean of its divisors is an integer number (165882991).

Almost surely, 2^331765981 is an apocalyptic number.

It is an amenable number.

331765981 is a deficient number, since it is larger than the sum of its proper divisors (1).

331765981 is an equidigital number, since it uses as much as digits as its factorization.

331765981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 43.

The square root of 331765981 is about 18214.4442956682. Note that the first 3 decimals coincide. The cubic root of 331765981 is about 692.2728251693.

The spelling of 331765981 in words is "three hundred thirty-one million, seven hundred sixty-five thousand, nine hundred eighty-one".