157747921 has 4 divisors (see below), whose sum is σ = 157773312. Its totient is φ = 157722532.

The previous prime is 157747901. The next prime is 157747927. The reversal of 157747921 is 129747751.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 157747921 - 2¹⁵ = 157715153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (157747927) 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 3 ways as a sum of consecutive naturals, for example, 3576 + ... + 18118.

It is an arithmetic number, because the mean of its divisors is an integer number (39443328).

Almost surely, 2^157747921 is an apocalyptic number.

It is an amenable number.

157747921 is a deficient number, since it is larger than the sum of its proper divisors (25391).

157747921 is a wasteful number, since it uses less digits than its factorization.

157747921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25390.

The product of its digits is 123480, while the sum is 43.

The square root of 157747921 is about 12559.7739231246. The cubic root of 157747921 is about 540.3243604551.

The spelling of 157747921 in words is "one hundred fifty-seven million, seven hundred forty-seven thousand, nine hundred twenty-one".