36401991 has 4 divisors (see below), whose sum is σ = 48535992. Its totient is φ = 24267992.

The previous prime is 36401987. The next prime is 36401993. The reversal of 36401991 is 19910463.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 36401991 - 2² = 36401987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (36401993) 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, 6066996 + ... + 6067001.

It is an arithmetic number, because the mean of its divisors is an integer number (12133998).

Almost surely, 2^36401991 is an apocalyptic number.

36401991 is a deficient number, since it is larger than the sum of its proper divisors (12134001).

36401991 is a wasteful number, since it uses less digits than its factorization.

36401991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12134000.

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 36401991 is about 6033.4062518614. The cubic root of 36401991 is about 331.4172016459.

The spelling of 36401991 in words is "thirty-six million, four hundred one thousand, nine hundred ninety-one".