406642521 has 4 divisors (see below), whose sum is σ = 542190032. Its totient is φ = 271095012.

The previous prime is 406642517. The next prime is 406642549. The reversal of 406642521 is 125246604.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 406642521 - 2² = 406642517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (406642501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67773751 + ... + 67773756.

It is an arithmetic number, because the mean of its divisors is an integer number (135547508).

Almost surely, 2^406642521 is an apocalyptic number.

It is an amenable number.

406642521 is a deficient number, since it is larger than the sum of its proper divisors (135547511).

406642521 is a wasteful number, since it uses less digits than its factorization.

406642521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135547510.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 406642521 is about 20165.3792674475. The cubic root of 406642521 is about 740.8624719953.

The spelling of 406642521 in words is "four hundred six million, six hundred forty-two thousand, five hundred twenty-one".