405152021 has 4 divisors (see below), whose sum is σ = 405460044. Its totient is φ = 404844000.

The previous prime is 405152017. The next prime is 405152023. The reversal of 405152021 is 120251504.

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 188650225 + 216501796 = 13735^2 + 14714^2 .

It is a cyclic number.

It is not a de Polignac number, because 405152021 - 2² = 405152017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 405151984 and 405152002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405152023) 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, 152030 + ... + 154671.

It is an arithmetic number, because the mean of its divisors is an integer number (101365011).

Almost surely, 2^405152021 is an apocalyptic number.

It is an amenable number.

405152021 is a deficient number, since it is larger than the sum of its proper divisors (308023).

405152021 is a wasteful number, since it uses less digits than its factorization.

405152021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308022.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 405152021 is about 20128.3884352424. The cubic root of 405152021 is about 739.9561825772.

The spelling of 405152021 in words is "four hundred five million, one hundred fifty-two thousand, twenty-one".