1390751821 has 2 divisors, whose sum is σ = 1390751822. Its totient is φ = 1390751820.

The previous prime is 1390751767. The next prime is 1390751899. The reversal of 1390751821 is 1281570931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1289528100 + 101223721 = 35910^2 + 10061^2 .

It is a cyclic number.

It is not a de Polignac number, because 1390751821 - 2¹⁹ = 1390227533 is a prime.

It is a super-2 number, since 2×1390751821² = 3868381255229632082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1390751221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695375910 + 695375911.

It is an arithmetic number, because the mean of its divisors is an integer number (695375911).

Almost surely, 2^1390751821 is an apocalyptic number.

It is an amenable number.

1390751821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1390751821 is an equidigital number, since it uses as much as digits as its factorization.

1390751821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 1390751821 is about 37292.7851065055. The cubic root of 1390751821 is about 1116.2202038572.

The spelling of 1390751821 in words is "one billion, three hundred ninety million, seven hundred fifty-one thousand, eight hundred twenty-one".