163256721 has 8 divisors (see below), whose sum is σ = 229132320. Its totient is φ = 103109472.

The previous prime is 163256713. The next prime is 163256741. The reversal of 163256721 is 127652361.

163256721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 163256721 - 2³ = 163256713 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (163256741) 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, 1432020 + ... + 1432133.

It is an arithmetic number, because the mean of its divisors is an integer number (28641540).

Almost surely, 2^163256721 is an apocalyptic number.

It is an amenable number.

163256721 is a deficient number, since it is larger than the sum of its proper divisors (65875599).

163256721 is a wasteful number, since it uses less digits than its factorization.

163256721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2864175.

The product of its digits is 15120, while the sum is 33.

The square root of 163256721 is about 12777.1953495280. The cubic root of 163256721 is about 546.5421864019.

The spelling of 163256721 in words is "one hundred sixty-three million, two hundred fifty-six thousand, seven hundred twenty-one".