157981605961 has 3 divisors (see below), whose sum is σ = 157982003431. Its totient is φ = 157981208492.

The previous prime is 157981605889. The next prime is 157981605979. The reversal of 157981605961 is 169506189751.

The square root of 157981605961 is 397469.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 85070805561 + 72910800400 = 291669^2 + 270020^2 .

It is not a de Polignac number, because 157981605961 - 2¹⁹ = 157981081673 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 157981605896 and 157981605905.

It is not an unprimeable number, because it can be changed into a prime (157981605161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 198735 + ... + 596203.

Almost surely, 2^157981605961 is an apocalyptic number.

157981605961 is the 397469-th square number.

157981605961 is the 198735-th centered octagonal number.

It is an amenable number.

157981605961 is a deficient number, since it is larger than the sum of its proper divisors (397470).

157981605961 is an frugal number, since it uses more digits than its factorization.

157981605961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 794938 (or 397469 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 58.

The spelling of 157981605961 in words is "one hundred fifty-seven billion, nine hundred eighty-one million, six hundred five thousand, nine hundred sixty-one".