406378721 has 8 divisors (see below), whose sum is σ = 479414784. Its totient is φ = 337088160.

The previous prime is 406378699. The next prime is 406378747. The reversal of 406378721 is 127873604.

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

It is a cyclic number.

It is not a de Polignac number, because 406378721 - 2⁶ = 406378657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (406378751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 936140 + ... + 936573.

It is an arithmetic number, because the mean of its divisors is an integer number (59926848).

Almost surely, 2^406378721 is an apocalyptic number.

It is an amenable number.

406378721 is a deficient number, since it is larger than the sum of its proper divisors (73036063).

406378721 is a wasteful number, since it uses less digits than its factorization.

406378721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1872751.

The product of its (nonzero) digits is 56448, while the sum is 38.

The square root of 406378721 is about 20158.8372928599. The cubic root of 406378721 is about 740.7022314994.

The spelling of 406378721 in words is "four hundred six million, three hundred seventy-eight thousand, seven hundred twenty-one".