156616721 has 12 divisors (see below), whose sum is σ = 160770960. Its totient is φ = 152559000.

The previous prime is 156616717. The next prime is 156616723. The reversal of 156616721 is 127616651.

It is not a de Polignac number, because 156616721 - 2² = 156616717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (156616723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 623846 + ... + 624096.

It is an arithmetic number, because the mean of its divisors is an integer number (13397580).

Almost surely, 2^156616721 is an apocalyptic number.

It is an amenable number.

156616721 is a deficient number, since it is larger than the sum of its proper divisors (4154239).

156616721 is an equidigital number, since it uses as much as digits as its factorization.

156616721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524 (or 457 counting only the distinct ones).

The product of its digits is 15120, while the sum is 35.

The square root of 156616721 is about 12514.6602430909. The cubic root of 156616721 is about 539.0297173836.

The spelling of 156616721 in words is "one hundred fifty-six million, six hundred sixteen thousand, seven hundred twenty-one".