157731475021 has 4 divisors (see below), whose sum is σ = 157807712700. Its totient is φ = 157655237344.

The previous prime is 157731475019. The next prime is 157731475061. The reversal of 157731475021 is 120574137751.

157731475021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120574137751 = 229 ⋅526524619.

It can be written as a sum of positive squares in 2 ways, for example, as 21654594025 + 136076880996 = 147155^2 + 368886^2 .

It is a cyclic number.

It is not a de Polignac number, because 157731475021 - 2¹ = 157731475019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157731475061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38115736 + ... + 38119873.

It is an arithmetic number, because the mean of its divisors is an integer number (39451928175).

Almost surely, 2^157731475021 is an apocalyptic number.

It is an amenable number.

157731475021 is a deficient number, since it is larger than the sum of its proper divisors (76237679).

157731475021 is an equidigital number, since it uses as much as digits as its factorization.

157731475021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76237678.

The product of its (nonzero) digits is 205800, while the sum is 43.

The spelling of 157731475021 in words is "one hundred fifty-seven billion, seven hundred thirty-one million, four hundred seventy-five thousand, twenty-one".