156781381 has 2 divisors, whose sum is σ = 156781382. Its totient is φ = 156781380.

The previous prime is 156781357. The next prime is 156781399. The reversal of 156781381 is 183187651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147841281 + 8940100 = 12159^2 + 2990^2 .

It is an emirp because it is prime and its reverse (183187651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156781381 - 2²³ = 148392773 is a prime.

It is a super-2 number, since 2×156781381² = 49160802856534322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156781301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78390690 + 78390691.

It is an arithmetic number, because the mean of its divisors is an integer number (78390691).

Almost surely, 2^156781381 is an apocalyptic number.

It is an amenable number.

156781381 is a deficient number, since it is larger than the sum of its proper divisors (1).

156781381 is an equidigital number, since it uses as much as digits as its factorization.

156781381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 40.

The square root of 156781381 is about 12521.2371992547. The cubic root of 156781381 is about 539.2185553439.

The spelling of 156781381 in words is "one hundred fifty-six million, seven hundred eighty-one thousand, three hundred eighty-one".