139979881 has 2 divisors, whose sum is σ = 139979882. Its totient is φ = 139979880.

The previous prime is 139979867. The next prime is 139979891. The reversal of 139979881 is 188979931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96353856 + 43626025 = 9816^2 + 6605^2 .

It is a cyclic number.

It is not a de Polignac number, because 139979881 - 2⁷ = 139979753 is a prime.

It is a super-2 number, since 2×139979881² = 39188734169548322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139979831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69989940 + 69989941.

It is an arithmetic number, because the mean of its divisors is an integer number (69989941).

Almost surely, 2^139979881 is an apocalyptic number.

It is an amenable number.

139979881 is a deficient number, since it is larger than the sum of its proper divisors (1).

139979881 is an equidigital number, since it uses as much as digits as its factorization.

139979881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 55.

The square root of 139979881 is about 11831.3093527302. The cubic root of 139979881 is about 519.2245357105.

Subtracting 139979881 from its reverse (188979931), we obtain a triangular number (49000050 = T₉₈₉₉).

The spelling of 139979881 in words is "one hundred thirty-nine million, nine hundred seventy-nine thousand, eight hundred eighty-one".