40664021 has 4 divisors (see below), whose sum is σ = 40794252. Its totient is φ = 40533792.

The previous prime is 40663991. The next prime is 40664027. The reversal of 40664021 is 12046604.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10797796 + 29866225 = 3286^2 + 5465^2 .

It is a cyclic number.

It is not a de Polignac number, because 40664021 - 2⁶ = 40663957 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 (40664027) 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, 64646 + ... + 65271.

It is an arithmetic number, because the mean of its divisors is an integer number (10198563).

Almost surely, 2^40664021 is an apocalyptic number.

It is an amenable number.

40664021 is a deficient number, since it is larger than the sum of its proper divisors (130231).

40664021 is a wasteful number, since it uses less digits than its factorization.

40664021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130230.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 40664021 is about 6376.8347163777. The cubic root of 40664021 is about 343.8772462907.

The spelling of 40664021 in words is "forty million, six hundred sixty-four thousand, twenty-one".