156780440681 has 4 divisors (see below), whose sum is σ = 157779042372. Its totient is φ = 155781838992.

The previous prime is 156780440653. The next prime is 156780440737. The reversal of 156780440681 is 186044087651.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14437224025 + 142343216656 = 120155^2 + 377284^2 .

It is a cyclic number.

It is not a de Polignac number, because 156780440681 - 2⁶ = 156780440617 is a prime.

It is a super-2 number, since 2×156780440681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (156780440651) 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, 499300610 + ... + 499300923.

It is an arithmetic number, because the mean of its divisors is an integer number (39444760593).

Almost surely, 2^156780440681 is an apocalyptic number.

It is an amenable number.

156780440681 is a deficient number, since it is larger than the sum of its proper divisors (998601691).

156780440681 is an equidigital number, since it uses as much as digits as its factorization.

156780440681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998601690.

The product of its (nonzero) digits is 1290240, while the sum is 50.

The spelling of 156780440681 in words is "one hundred fifty-six billion, seven hundred eighty million, four hundred forty thousand, six hundred eighty-one".