1656378321 has 16 divisors (see below), whose sum is σ = 2382543744. Its totient is φ = 1017529344.

The previous prime is 1656378259. The next prime is 1656378337. The reversal of 1656378321 is 1238736561.

It is not a de Polignac number, because 1656378321 - 2⁹ = 1656377809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1656370321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14301 + ... + 59306.

It is an arithmetic number, because the mean of its divisors is an integer number (148908984).

Almost surely, 2^1656378321 is an apocalyptic number.

It is an amenable number.

1656378321 is a deficient number, since it is larger than the sum of its proper divisors (726165423).

1656378321 is a wasteful number, since it uses less digits than its factorization.

1656378321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74200.

The product of its digits is 181440, while the sum is 42.

The square root of 1656378321 is about 40698.6279989879. The cubic root of 1656378321 is about 1183.1864277240.

The spelling of 1656378321 in words is "one billion, six hundred fifty-six million, three hundred seventy-eight thousand, three hundred twenty-one".