993538471621 has 2 divisors, whose sum is σ = 993538471622. Its totient is φ = 993538471620.

The previous prime is 993538471591. The next prime is 993538471799. The reversal of 993538471621 is 126174835399.

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., 745822232100 + 247716239521 = 863610^2 + 497711^2 .

It is an emirp because it is prime and its reverse (126174835399) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 993538471621 - 2⁷ = 993538471493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (993548471621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 496769235810 + 496769235811.

It is an arithmetic number, because the mean of its divisors is an integer number (496769235811).

Almost surely, 2^993538471621 is an apocalyptic number.

It is an amenable number.

993538471621 is a deficient number, since it is larger than the sum of its proper divisors (1).

993538471621 is an equidigital number, since it uses as much as digits as its factorization.

993538471621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9797760, while the sum is 58.

The spelling of 993538471621 in words is "nine hundred ninety-three billion, five hundred thirty-eight million, four hundred seventy-one thousand, six hundred twenty-one".