1399310821 has 2 divisors, whose sum is σ = 1399310822. Its totient is φ = 1399310820.

The previous prime is 1399310791. The next prime is 1399310833. The reversal of 1399310821 is 1280139931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1375593921 + 23716900 = 37089^2 + 4870^2 .

It is a cyclic number.

It is not a de Polignac number, because 1399310821 - 2¹¹ = 1399308773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1399310221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 699655410 + 699655411.

It is an arithmetic number, because the mean of its divisors is an integer number (699655411).

Almost surely, 2^1399310821 is an apocalyptic number.

It is an amenable number.

1399310821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1399310821 is an equidigital number, since it uses as much as digits as its factorization.

1399310821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 1399310821 is about 37407.3631922914. The cubic root of 1399310821 is about 1118.5053460169.

The spelling of 1399310821 in words is "one billion, three hundred ninety-nine million, three hundred ten thousand, eight hundred twenty-one".