75556661 has 2 divisors, whose sum is σ = 75556662. Its totient is φ = 75556660.

The previous prime is 75556651. The next prime is 75556667. The reversal of 75556661 is 16665557.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44809636 + 30747025 = 6694^2 + 5545^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-75556661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75556667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37778330 + 37778331.

It is an arithmetic number, because the mean of its divisors is an integer number (37778331).

Almost surely, 2^75556661 is an apocalyptic number.

It is an amenable number.

75556661 is a deficient number, since it is larger than the sum of its proper divisors (1).

75556661 is an equidigital number, since it uses as much as digits as its factorization.

75556661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 41.

The square root of 75556661 is about 8692.3334611599. Note that the first 3 decimals coincide. The cubic root of 75556661 is about 422.7571087754.

The spelling of 75556661 in words is "seventy-five million, five hundred fifty-six thousand, six hundred sixty-one".