75561497021 has 2 divisors, whose sum is σ = 75561497022. Its totient is φ = 75561497020.

The previous prime is 75561496993. The next prime is 75561497029. The reversal of 75561497021 is 12079416557.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67977525625 + 7583971396 = 260725^2 + 87086^2 .

It is a cyclic number.

It is not a de Polignac number, because 75561497021 - 2⁶ = 75561496957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75561497029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37780748510 + 37780748511.

It is an arithmetic number, because the mean of its divisors is an integer number (37780748511).

Almost surely, 2^75561497021 is an apocalyptic number.

It is an amenable number.

75561497021 is a deficient number, since it is larger than the sum of its proper divisors (1).

75561497021 is an equidigital number, since it uses as much as digits as its factorization.

75561497021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 529200, while the sum is 47.

The spelling of 75561497021 in words is "seventy-five billion, five hundred sixty-one million, four hundred ninety-seven thousand, twenty-one".