99975661 has 2 divisors, whose sum is σ = 99975662. Its totient is φ = 99975660.

The previous prime is 99975653. The next prime is 99975679. The reversal of 99975661 is 16657999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99800100 + 175561 = 9990^2 + 419^2 .

It is an emirp because it is prime and its reverse (16657999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99975661 - 2³ = 99975653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 99975599 and 99975608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99975061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49987830 + 49987831.

It is an arithmetic number, because the mean of its divisors is an integer number (49987831).

Almost surely, 2^99975661 is an apocalyptic number.

It is an amenable number.

99975661 is a deficient number, since it is larger than the sum of its proper divisors (1).

99975661 is an equidigital number, since it uses as much as digits as its factorization.

99975661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 918540, while the sum is 52.

The square root of 99975661 is about 9998.7829759426. The cubic root of 99975661 is about 464.1212230955.

The spelling of 99975661 in words is "ninety-nine million, nine hundred seventy-five thousand, six hundred sixty-one".