1621621579937 has 2 divisors, whose sum is σ = 1621621579938. Its totient is φ = 1621621579936.

The previous prime is 1621621579889. The next prime is 1621621579939. The reversal of 1621621579937 is 7399751261261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1588126723681 + 33494856256 = 1260209^2 + 183016^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621621579937 - 2¹² = 1621621575841 is a prime.

Together with 1621621579939, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1621621579939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810810789968 + 810810789969.

It is an arithmetic number, because the mean of its divisors is an integer number (810810789969).

Almost surely, 2^{1621621579937} is an apocalyptic number.

It is an amenable number.

1621621579937 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621621579937 is an equidigital number, since it uses as much as digits as its factorization.

1621621579937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8573040, while the sum is 59.

The spelling of 1621621579937 in words is "one trillion, six hundred twenty-one billion, six hundred twenty-one million, five hundred seventy-nine thousand, nine hundred thirty-seven".