157994621 has 4 divisors (see below), whose sum is σ = 158351712. Its totient is φ = 157637532.

The previous prime is 157994611. The next prime is 157994623. The reversal of 157994621 is 126499751.

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 an emirpimes, since its reverse is a distinct semiprime: 126499751 = 7 ⋅18071393.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157994621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157994623) 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, 177881 + ... + 178766.

It is an arithmetic number, because the mean of its divisors is an integer number (39587928).

Almost surely, 2^157994621 is an apocalyptic number.

It is an amenable number.

157994621 is a deficient number, since it is larger than the sum of its proper divisors (357091).

157994621 is an equidigital number, since it uses as much as digits as its factorization.

157994621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357090.

The product of its digits is 136080, while the sum is 44.

The square root of 157994621 is about 12569.5911230239. The cubic root of 157994621 is about 540.6058825855.

The spelling of 157994621 in words is "one hundred fifty-seven million, nine hundred ninety-four thousand, six hundred twenty-one".