1642420621 has 2 divisors, whose sum is σ = 1642420622. Its totient is φ = 1642420620.

The previous prime is 1642420567. The next prime is 1642420627. The reversal of 1642420621 is 1260242461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 836655625 + 805764996 = 28925^2 + 28386^2 .

It is a cyclic number.

It is not a de Polignac number, because 1642420621 - 2²³ = 1634032013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1642420621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1642420627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821210310 + 821210311.

It is an arithmetic number, because the mean of its divisors is an integer number (821210311).

Almost surely, 2^1642420621 is an apocalyptic number.

It is an amenable number.

1642420621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1642420621 is an equidigital number, since it uses as much as digits as its factorization.

1642420621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 1642420621 is about 40526.7889302866. The cubic root of 1642420621 is about 1179.8536208829.

The spelling of 1642420621 in words is "one billion, six hundred forty-two million, four hundred twenty thousand, six hundred twenty-one".