409220721 has 64 divisors (see below), whose sum is σ = 751779840. Its totient is φ = 214228800.

The previous prime is 409220633. The next prime is 409220731. The reversal of 409220721 is 127022904.

It is not a de Polignac number, because 409220721 - 2¹⁸ = 408958577 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (409220731) 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 63 ways as a sum of consecutive naturals, for example, 370456 + ... + 371558.

It is an arithmetic number, because the mean of its divisors is an integer number (11746560).

Almost surely, 2^409220721 is an apocalyptic number.

It is an amenable number.

409220721 is a deficient number, since it is larger than the sum of its proper divisors (342559119).

409220721 is a wasteful number, since it uses less digits than its factorization.

409220721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1283 (or 1277 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 409220721 is about 20229.2046556458. The cubic root of 409220721 is about 742.4249163949.

The spelling of 409220721 in words is "four hundred nine million, two hundred twenty thousand, seven hundred twenty-one".