1390390891 has 2 divisors, whose sum is σ = 1390390892. Its totient is φ = 1390390890.

The previous prime is 1390390879. The next prime is 1390390957. The reversal of 1390390891 is 1980930931.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1390390891 is a prime.

It is not a weakly prime, because it can be changed into another prime (1390390091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695195445 + 695195446.

It is an arithmetic number, because the mean of its divisors is an integer number (695195446).

Almost surely, 2^1390390891 is an apocalyptic number.

1390390891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1390390891 is an equidigital number, since it uses as much as digits as its factorization.

1390390891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 43.

The square root of 1390390891 is about 37287.9456527173. The cubic root of 1390390891 is about 1116.1236344553.

The spelling of 1390390891 in words is "one billion, three hundred ninety million, three hundred ninety thousand, eight hundred ninety-one".