36645991 has 4 divisors (see below), whose sum is σ = 36736000. Its totient is φ = 36555984.

The previous prime is 36645941. The next prime is 36645997. The reversal of 36645991 is 19954663.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19954663 = 167 ⋅119489.

It is a cyclic number.

It is not a de Polignac number, because 36645991 - 2¹⁹ = 36121703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (36645997) 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, 44391 + ... + 45208.

It is an arithmetic number, because the mean of its divisors is an integer number (9184000).

Almost surely, 2^36645991 is an apocalyptic number.

36645991 is a deficient number, since it is larger than the sum of its proper divisors (90009).

36645991 is an equidigital number, since it uses as much as digits as its factorization.

36645991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90008.

The product of its digits is 174960, while the sum is 43.

The square root of 36645991 is about 6053.5932304706. The cubic root of 36645991 is about 332.1560420733.

It can be divided in two parts, 36645 and 991, that added together give a square (37636 = 194²).

The spelling of 36645991 in words is "thirty-six million, six hundred forty-five thousand, nine hundred ninety-one".