406390821 has 8 divisors (see below), whose sum is σ = 547943040. Its totient is φ = 267882912.

The previous prime is 406390813. The next prime is 406390823. The reversal of 406390821 is 128093604.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 406390821 - 2³ = 406390813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (406390823) 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, 760765 + ... + 761298.

It is an arithmetic number, because the mean of its divisors is an integer number (68492880).

Almost surely, 2^406390821 is an apocalyptic number.

It is an amenable number.

406390821 is a deficient number, since it is larger than the sum of its proper divisors (141552219).

406390821 is a wasteful number, since it uses less digits than its factorization.

406390821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1522155.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 406390821 is about 20159.1374071412. The cubic root of 406390821 is about 740.7095829408.

The spelling of 406390821 in words is "four hundred six million, three hundred ninety thousand, eight hundred twenty-one".