139157781 has 8 divisors (see below), whose sum is σ = 212049984. Its totient is φ = 79518720.

The previous prime is 139157773. The next prime is 139157803. The reversal of 139157781 is 187751931.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 139157781 - 2³ = 139157773 is a prime.

It is a super-2 number, since 2×139157781² = 38729776025687922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139157281) 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 7 ways as a sum of consecutive naturals, for example, 3313260 + ... + 3313301.

It is an arithmetic number, because the mean of its divisors is an integer number (26506248).

Almost surely, 2^139157781 is an apocalyptic number.

It is an amenable number.

139157781 is a deficient number, since it is larger than the sum of its proper divisors (72892203).

139157781 is an equidigital number, since it uses as much as digits as its factorization.

139157781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6626571.

The product of its digits is 52920, while the sum is 42.

The square root of 139157781 is about 11796.5156296256. The cubic root of 139157781 is about 518.2060730050.

The spelling of 139157781 in words is "one hundred thirty-nine million, one hundred fifty-seven thousand, seven hundred eighty-one".