1390408421 has 2 divisors, whose sum is σ = 1390408422. Its totient is φ = 1390408420.

The previous prime is 1390408403. The next prime is 1390408501. The reversal of 1390408421 is 1248040931.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1275275521 + 115132900 = 35711^2 + 10730^2 .

It is an emirp because it is prime and its reverse (1248040931) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1390408421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1390608421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695204210 + 695204211.

It is an arithmetic number, because the mean of its divisors is an integer number (695204211).

Almost surely, 2^1390408421 is an apocalyptic number.

It is an amenable number.

1390408421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1390408421 is an equidigital number, since it uses as much as digits as its factorization.

1390408421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 1390408421 is about 37288.1807145374. The cubic root of 1390408421 is about 1116.1283251182.

The spelling of 1390408421 in words is "one billion, three hundred ninety million, four hundred eight thousand, four hundred twenty-one".