405924021 has 8 divisors (see below), whose sum is σ = 601368960. Its totient is φ = 270615996.

The previous prime is 405924017. The next prime is 405924023. The reversal of 405924021 is 120429504.

It is not a de Polignac number, because 405924021 - 2² = 405924017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 15034223 = 405924021 / (4 + 0 + 5 + 9 + 2 + 4 + 0 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405924023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7517085 + ... + 7517138.

It is an arithmetic number, because the mean of its divisors is an integer number (75171120).

Almost surely, 2^405924021 is an apocalyptic number.

It is an amenable number.

405924021 is a deficient number, since it is larger than the sum of its proper divisors (195444939).

405924021 is a wasteful number, since it uses less digits than its factorization.

405924021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15034232 (or 15034226 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 405924021 is about 20147.5562041653. The cubic root of 405924021 is about 740.4258694260.

The spelling of 405924021 in words is "four hundred five million, nine hundred twenty-four thousand, twenty-one".