157890620821 has 4 divisors (see below), whose sum is σ = 157900904172. Its totient is φ = 157880337472.

The previous prime is 157890620729. The next prime is 157890620851. The reversal of 157890620821 is 128026098751.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 135489511921 + 22401108900 = 368089^2 + 149670^2 .

It is a cyclic number.

It is not a de Polignac number, because 157890620821 - 2¹⁷ = 157890489749 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 (157890620851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5118610 + ... + 5149363.

It is an arithmetic number, because the mean of its divisors is an integer number (39475226043).

Almost surely, 2^157890620821 is an apocalyptic number.

It is an amenable number.

157890620821 is a deficient number, since it is larger than the sum of its proper divisors (10283351).

157890620821 is a wasteful number, since it uses less digits than its factorization.

157890620821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10283350.

The product of its (nonzero) digits is 483840, while the sum is 49.

The spelling of 157890620821 in words is "one hundred fifty-seven billion, eight hundred ninety million, six hundred twenty thousand, eight hundred twenty-one".