1392776981 has 2 divisors, whose sum is σ = 1392776982. Its totient is φ = 1392776980.

The previous prime is 1392776963. The next prime is 1392776993. The reversal of 1392776981 is 1896772931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1299963025 + 92813956 = 36055^2 + 9634^2 .

It is an emirp because it is prime and its reverse (1896772931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1392776981 - 2²² = 1388582677 is a prime.

It is a super-2 number, since 2×1392776981² = 3879655437606948722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1392776941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 696388490 + 696388491.

It is an arithmetic number, because the mean of its divisors is an integer number (696388491).

Almost surely, 2^1392776981 is an apocalyptic number.

It is an amenable number.

1392776981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1392776981 is an equidigital number, since it uses as much as digits as its factorization.

1392776981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1143072, while the sum is 53.

The square root of 1392776981 is about 37319.9273981073. The cubic root of 1392776981 is about 1116.7617402480.

The spelling of 1392776981 in words is "one billion, three hundred ninety-two million, seven hundred seventy-six thousand, nine hundred eighty-one".