36661991 has 2 divisors, whose sum is σ = 36661992. Its totient is φ = 36661990.

The previous prime is 36661981. The next prime is 36661993. The reversal of 36661991 is 19916663.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 36661991 - 2¹⁴ = 36645607 is a prime.

Together with 36661993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (36661993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18330995 + 18330996.

It is an arithmetic number, because the mean of its divisors is an integer number (18330996).

Almost surely, 2^36661991 is an apocalyptic number.

36661991 is a deficient number, since it is larger than the sum of its proper divisors (1).

36661991 is an equidigital number, since it uses as much as digits as its factorization.

36661991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52488, while the sum is 41.

The square root of 36661991 is about 6054.9146154178. The cubic root of 36661991 is about 332.2043759043.

The spelling of 36661991 in words is "thirty-six million, six hundred sixty-one thousand, nine hundred ninety-one".