157804021 has 2 divisors, whose sum is σ = 157804022. Its totient is φ = 157804020.

The previous prime is 157804019. The next prime is 157804033. The reversal of 157804021 is 120408751.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132503121 + 25300900 = 11511^2 + 5030^2 .

It is a cyclic number.

It is not a de Polignac number, because 157804021 - 2¹ = 157804019 is a prime.

Together with 157804019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157814021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78902010 + 78902011.

It is an arithmetic number, because the mean of its divisors is an integer number (78902011).

Almost surely, 2^157804021 is an apocalyptic number.

It is an amenable number.

157804021 is a deficient number, since it is larger than the sum of its proper divisors (1).

157804021 is an equidigital number, since it uses as much as digits as its factorization.

157804021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 157804021 is about 12562.0070450545. The cubic root of 157804021 is about 540.3884048365.

The spelling of 157804021 in words is "one hundred fifty-seven million, eight hundred four thousand, twenty-one".