75007878661 has 2 divisors, whose sum is σ = 75007878662. Its totient is φ = 75007878660.

The previous prime is 75007878637. The next prime is 75007878677. The reversal of 75007878661 is 16687870057.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60806628100 + 14201250561 = 246590^2 + 119169^2 .

It is an emirp because it is prime and its reverse (16687870057) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 75007878661 - 2³³ = 66417944069 is a prime.

It is a super-2 number, since 2×75007878661² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75007878161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37503939330 + 37503939331.

It is an arithmetic number, because the mean of its divisors is an integer number (37503939331).

Almost surely, 2^75007878661 is an apocalyptic number.

It is an amenable number.

75007878661 is a deficient number, since it is larger than the sum of its proper divisors (1).

75007878661 is an equidigital number, since it uses as much as digits as its factorization.

75007878661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3951360, while the sum is 55.

The spelling of 75007878661 in words is "seventy-five billion, seven million, eight hundred seventy-eight thousand, six hundred sixty-one".