1390287881 has 2 divisors, whose sum is σ = 1390287882. Its totient is φ = 1390287880.

The previous prime is 1390287823. The next prime is 1390287889. The reversal of 1390287881 is 1887820931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 928725625 + 461562256 = 30475^2 + 21484^2 .

It is an emirp because it is prime and its reverse (1887820931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1390287881 - 2¹⁸ = 1390025737 is a prime.

It is a super-2 number, since 2×1390287881² = 3865800784110940322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1390287889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695143940 + 695143941.

It is an arithmetic number, because the mean of its divisors is an integer number (695143941).

Almost surely, 2^1390287881 is an apocalyptic number.

It is an amenable number.

1390287881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1390287881 is an equidigital number, since it uses as much as digits as its factorization.

1390287881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 47.

The square root of 1390287881 is about 37286.5643496421. The cubic root of 1390287881 is about 1116.0960703278.

The spelling of 1390287881 in words is "one billion, three hundred ninety million, two hundred eighty-seven thousand, eight hundred eighty-one".