156991541 has 6 divisors (see below), whose sum is σ = 182622870. Its totient is φ = 134564136.

The previous prime is 156991531. The next prime is 156991543. The reversal of 156991541 is 145199651.

It can be written as a sum of positive squares in only one way, i.e., 118178641 + 38812900 = 10871^2 + 6230^2 .

It is not a de Polignac number, because 156991541 - 2⁶ = 156991477 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 (156991543) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1601906 + ... + 1602003.

It is an arithmetic number, because the mean of its divisors is an integer number (30437145).

Almost surely, 2^156991541 is an apocalyptic number.

It is an amenable number.

156991541 is a deficient number, since it is larger than the sum of its proper divisors (25631329).

156991541 is an equidigital number, since it uses as much as digits as its factorization.

156991541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3203923 (or 3203916 counting only the distinct ones).

The product of its digits is 48600, while the sum is 41.

The square root of 156991541 is about 12529.6265307470. The cubic root of 156991541 is about 539.4593823557.

The spelling of 156991541 in words is "one hundred fifty-six million, nine hundred ninety-one thousand, five hundred forty-one".