157628721 has 8 divisors (see below), whose sum is σ = 210329344. Its totient is φ = 105006960.

The previous prime is 157628711. The next prime is 157628747. The reversal of 157628721 is 127826751.

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

It is not a de Polignac number, because 157628721 - 2⁷ = 157628593 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 157628721.

It is not an unprimeable number, because it can be changed into a prime (157628711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14881 + ... + 23166.

It is an arithmetic number, because the mean of its divisors is an integer number (26291168).

Almost surely, 2^157628721 is an apocalyptic number.

It is an amenable number.

157628721 is a deficient number, since it is larger than the sum of its proper divisors (52700623).

157628721 is a wasteful number, since it uses less digits than its factorization.

157628721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39431.

The product of its digits is 47040, while the sum is 39.

The square root of 157628721 is about 12555.0277180100. The cubic root of 157628721 is about 540.1882299907.

The spelling of 157628721 in words is "one hundred fifty-seven million, six hundred twenty-eight thousand, seven hundred twenty-one".