156644981 has 2 divisors, whose sum is σ = 156644982. Its totient is φ = 156644980.

The previous prime is 156644977. The next prime is 156644993. The reversal of 156644981 is 189446651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 96334225 + 60310756 = 9815^2 + 7766^2 .

It is a cyclic number.

It is not a de Polignac number, because 156644981 - 2² = 156644977 is a prime.

It is a super-2 number, since 2×156644981² = 49075300144980722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156694981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78322490 + 78322491.

It is an arithmetic number, because the mean of its divisors is an integer number (78322491).

Almost surely, 2^156644981 is an apocalyptic number.

It is an amenable number.

156644981 is a deficient number, since it is larger than the sum of its proper divisors (1).

156644981 is an equidigital number, since it uses as much as digits as its factorization.

156644981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 44.

The square root of 156644981 is about 12515.7892679607. The cubic root of 156644981 is about 539.0621363649.

The spelling of 156644981 in words is "one hundred fifty-six million, six hundred forty-four thousand, nine hundred eighty-one".