406636021 has 32 divisors (see below), whose sum is σ = 482549760. Its totient is φ = 338817600.

The previous prime is 406636019. The next prime is 406636063. The reversal of 406636021 is 120636604.

It is not a de Polignac number, because 406636021 - 2¹ = 406636019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (406636121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1089991 + ... + 1090363.

It is an arithmetic number, because the mean of its divisors is an integer number (15079680).

Almost surely, 2^406636021 is an apocalyptic number.

It is an amenable number.

406636021 is a deficient number, since it is larger than the sum of its proper divisors (75913739).

406636021 is a wasteful number, since it uses less digits than its factorization.

406636021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 577.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 406636021 is about 20165.2180994900. The cubic root of 406636021 is about 740.8585245218.

The spelling of 406636021 in words is "four hundred six million, six hundred thirty-six thousand, twenty-one".