163630428659721 has 9 divisors (see below), whose sum is σ = 236355119050791. Its totient is φ = 109086926856192.

The previous prime is 163630428659689. The next prime is 163630428659729. The reversal of 163630428659721 is 127956824036361.

The square root of 163630428659721 is 12791811.

It is a perfect power (a square), and thus also a powerful number.

163630428659721 is a `hidden beast` number, since 1 + 6 + 3 + 6 + 30 + 4 + 2 + 8 + 6 + 597 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 153725157974025 + 9905270685696 = 12398595^2 + 3147264^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 163630428659721 - 2⁵ = 163630428659689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (163630428659729) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 36243465 + ... + 40507401.

It is a 3-persistent number, because k⋅163630428659721 is pandigital for 1 ≤ k ≤ 3, but not for k = 4.

Almost surely, 2^{163630428659721} is an apocalyptic number.

163630428659721 is the 12791811-st square number.

163630428659721 is the 6395906-th centered octagonal number.

It is an amenable number.

163630428659721 is a deficient number, since it is larger than the sum of its proper divisors (72724690391070).

163630428659721 is an frugal number, since it uses more digits than its factorization.

163630428659721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8527880 (or 4263940 counting only the distinct ones).

The product of its (nonzero) digits is 78382080, while the sum is 63.

The spelling of 163630428659721 in words is "one hundred sixty-three trillion, six hundred thirty billion, four hundred twenty-eight million, six hundred fifty-nine thousand, seven hundred twenty-one".