1621064643829 has 2 divisors, whose sum is σ = 1621064643830. Its totient is φ = 1621064643828.

The previous prime is 1621064643791. The next prime is 1621064643851. The reversal of 1621064643829 is 9283464601261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1619060290929 + 2004352900 = 1272423^2 + 44770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621064643829 - 2⁷ = 1621064643701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1621064640829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810532321914 + 810532321915.

It is an arithmetic number, because the mean of its divisors is an integer number (810532321915).

Almost surely, 2^{1621064643829} is an apocalyptic number.

It is an amenable number.

1621064643829 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621064643829 is an equidigital number, since it uses as much as digits as its factorization.

1621064643829 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2985984, while the sum is 52.

The spelling of 1621064643829 in words is "one trillion, six hundred twenty-one billion, sixty-four million, six hundred forty-three thousand, eight hundred twenty-nine".