7564428661 has 2 divisors, whose sum is σ = 7564428662. Its totient is φ = 7564428660.

The previous prime is 7564428601. The next prime is 7564428719. The reversal of 7564428661 is 1668244657.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3880667025 + 3683761636 = 62295^2 + 60694^2 .

It is a cyclic number.

It is not a de Polignac number, because 7564428661 - 2⁷ = 7564428533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7564428601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3782214330 + 3782214331.

It is an arithmetic number, because the mean of its divisors is an integer number (3782214331).

Almost surely, 2^7564428661 is an apocalyptic number.

It is an amenable number.

7564428661 is a deficient number, since it is larger than the sum of its proper divisors (1).

7564428661 is an equidigital number, since it uses as much as digits as its factorization.

7564428661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1935360, while the sum is 49.

The square root of 7564428661 is about 86973.7239687942. The cubic root of 7564428661 is about 1963.0229505573.

The spelling of 7564428661 in words is "seven billion, five hundred sixty-four million, four hundred twenty-eight thousand, six hundred sixty-one".