7942189621 has 2 divisors, whose sum is σ = 7942189622. Its totient is φ = 7942189620.

The previous prime is 7942189589. The next prime is 7942189627. The reversal of 7942189621 is 1269812497.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7320684721 + 621504900 = 85561^2 + 24930^2 .

It is a cyclic number.

It is not a de Polignac number, because 7942189621 - 2⁵ = 7942189589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7942189627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3971094810 + 3971094811.

It is an arithmetic number, because the mean of its divisors is an integer number (3971094811).

Almost surely, 2^7942189621 is an apocalyptic number.

It is an amenable number.

7942189621 is a deficient number, since it is larger than the sum of its proper divisors (1).

7942189621 is an equidigital number, since it uses as much as digits as its factorization.

7942189621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 49.

The square root of 7942189621 is about 89118.9633074802. The cubic root of 7942189621 is about 1995.1708172990.

The spelling of 7942189621 in words is "seven billion, nine hundred forty-two million, one hundred eighty-nine thousand, six hundred twenty-one".