36571981 has 4 divisors (see below), whose sum is σ = 38723292. Its totient is φ = 34420672.

The previous prime is 36571963. The next prime is 36571993. The reversal of 36571981 is 18917563.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18917563 = 7 ⋅2702509.

It can be written as a sum of positive squares in 2 ways, for example, as 20331081 + 16240900 = 4509^2 + 4030^2 .

It is a cyclic number.

It is not a de Polignac number, because 36571981 - 2⁵ = 36571949 is a prime.

It is a super-2 number, since 2×36571981² = 2675019588528722, 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 (36571921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1075630 + ... + 1075663.

It is an arithmetic number, because the mean of its divisors is an integer number (9680823).

Almost surely, 2^36571981 is an apocalyptic number.

It is an amenable number.

36571981 is a deficient number, since it is larger than the sum of its proper divisors (2151311).

36571981 is a wasteful number, since it uses less digits than its factorization.

36571981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2151310.

The product of its digits is 45360, while the sum is 40.

The square root of 36571981 is about 6047.4772426194. The cubic root of 36571981 is about 331.9322846606.

The spelling of 36571981 in words is "thirty-six million, five hundred seventy-one thousand, nine hundred eighty-one".