36557981 has 2 divisors, whose sum is σ = 36557982. Its totient is φ = 36557980.

The previous prime is 36557923. The next prime is 36557987. The reversal of 36557981 is 18975563.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20025625 + 16532356 = 4475^2 + 4066^2 .

It is a cyclic number.

It is not a de Polignac number, because 36557981 - 2¹⁰ = 36556957 is a prime.

It is a super-2 number, since 2×36557981² = 2672971949592722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (36557987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18278990 + 18278991.

It is an arithmetic number, because the mean of its divisors is an integer number (18278991).

Almost surely, 2^36557981 is an apocalyptic number.

It is an amenable number.

36557981 is a deficient number, since it is larger than the sum of its proper divisors (1).

36557981 is an equidigital number, since it uses as much as digits as its factorization.

36557981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 226800, while the sum is 44.

The square root of 36557981 is about 6046.3196243665. The cubic root of 36557981 is about 331.8899239520.

The spelling of 36557981 in words is "thirty-six million, five hundred fifty-seven thousand, nine hundred eighty-one".