401645021 has 16 divisors (see below), whose sum is σ = 433963008. Its totient is φ = 370642800.

The previous prime is 401645017. The next prime is 401645059. The reversal of 401645021 is 120546104.

It is a cyclic number.

It is not a de Polignac number, because 401645021 - 2² = 401645017 is a prime.

It is a super-2 number, since 2×401645021² = 322637445788180882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (401645081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 306650 + ... + 307956.

It is an arithmetic number, because the mean of its divisors is an integer number (27122688).

Almost surely, 2^401645021 is an apocalyptic number.

It is an amenable number.

401645021 is a deficient number, since it is larger than the sum of its proper divisors (32317987).

401645021 is a wasteful number, since it uses less digits than its factorization.

401645021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1792.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 401645021 is about 20041.0833290020. The cubic root of 401645021 is about 737.8149697830.

The spelling of 401645021 in words is "four hundred one million, six hundred forty-five thousand, twenty-one".