163402721 has 8 divisors (see below), whose sum is σ = 164642280. Its totient is φ = 162168192.

The previous prime is 163402711. The next prime is 163402727. The reversal of 163402721 is 127204361.

It can be written as a sum of positive squares in 4 ways, for example, as 97614400 + 65788321 = 9880^2 + 8111^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-163402721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (163402727) 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, 84461 + ... + 86373.

It is an arithmetic number, because the mean of its divisors is an integer number (20580285).

Almost surely, 2^163402721 is an apocalyptic number.

It is an amenable number.

163402721 is a deficient number, since it is larger than the sum of its proper divisors (1239559).

163402721 is a wasteful number, since it uses less digits than its factorization.

163402721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2515.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 163402721 is about 12782.9073766495. The cubic root of 163402721 is about 546.7050615425.

The spelling of 163402721 in words is "one hundred sixty-three million, four hundred two thousand, seven hundred twenty-one".