139553621 has 2 divisors, whose sum is σ = 139553622. Its totient is φ = 139553620.

The previous prime is 139553593. The next prime is 139553647. The reversal of 139553621 is 126355931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 108972721 + 30580900 = 10439^2 + 5530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139553621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139553321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69776810 + 69776811.

It is an arithmetic number, because the mean of its divisors is an integer number (69776811).

Almost surely, 2^139553621 is an apocalyptic number.

It is an amenable number.

139553621 is a deficient number, since it is larger than the sum of its proper divisors (1).

139553621 is an equidigital number, since it uses as much as digits as its factorization.

139553621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24300, while the sum is 35.

The square root of 139553621 is about 11813.2815508647. The cubic root of 139553621 is about 518.6969606390.

It can be divided in two parts, 13955 and 3621, that added together give a cube (17576 = 26³).

The spelling of 139553621 in words is "one hundred thirty-nine million, five hundred fifty-three thousand, six hundred twenty-one".