1621726210553 has 2 divisors, whose sum is σ = 1621726210554. Its totient is φ = 1621726210552.

The previous prime is 1621726210541. The next prime is 1621726210619. The reversal of 1621726210553 is 3550126271261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1397568467344 + 224157743209 = 1182188^2 + 473453^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621726210553 - 2¹⁰ = 1621726209529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1621726210553.

It is not a weakly prime, because it can be changed into another prime (1621726215553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810863105276 + 810863105277.

It is an arithmetic number, because the mean of its divisors is an integer number (810863105277).

Almost surely, 2^{1621726210553} is an apocalyptic number.

It is an amenable number.

1621726210553 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621726210553 is an equidigital number, since it uses as much as digits as its factorization.

1621726210553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 151200, while the sum is 41.

The spelling of 1621726210553 in words is "one trillion, six hundred twenty-one billion, seven hundred twenty-six million, two hundred ten thousand, five hundred fifty-three".