1399847921 has 2 divisors, whose sum is σ = 1399847922. Its totient is φ = 1399847920.

The previous prime is 1399847909. The next prime is 1399847957. The reversal of 1399847921 is 1297489931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1213825600 + 186022321 = 34840^2 + 13639^2 .

It is a cyclic number.

It is not a de Polignac number, because 1399847921 - 2¹⁸ = 1399585777 is a prime.

It is not a weakly prime, because it can be changed into another prime (1399847221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 699923960 + 699923961.

It is an arithmetic number, because the mean of its divisors is an integer number (699923961).

Almost surely, 2^1399847921 is an apocalyptic number.

It is an amenable number.

1399847921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1399847921 is an equidigital number, since it uses as much as digits as its factorization.

1399847921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 53.

The square root of 1399847921 is about 37414.5415714265. The cubic root of 1399847921 is about 1118.6484336871.

The spelling of 1399847921 in words is "one billion, three hundred ninety-nine million, eight hundred forty-seven thousand, nine hundred twenty-one".