99211561 has 2 divisors, whose sum is σ = 99211562. Its totient is φ = 99211560.

The previous prime is 99211543. The next prime is 99211571. The reversal of 99211561 is 16511299.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68475625 + 30735936 = 8275^2 + 5544^2 .

It is a cyclic number.

It is not a de Polignac number, because 99211561 - 2⁷ = 99211433 is a prime.

It is the 9961-st Hogben number.

It is equal to p_5718616 and since 99211561 and 5718616 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (99211571) by changing a digit.

It is a nontrivial repunit in base 9960.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49605780 + 49605781.

It is an arithmetic number, because the mean of its divisors is an integer number (49605781).

Almost surely, 2^99211561 is an apocalyptic number.

It is an amenable number.

99211561 is a deficient number, since it is larger than the sum of its proper divisors (1).

99211561 is an equidigital number, since it uses as much as digits as its factorization.

99211561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4860, while the sum is 34.

The square root of 99211561 is about 9960.5000376487. The cubic root of 99211561 is about 462.9357933814.

The spelling of 99211561 in words is "ninety-nine million, two hundred eleven thousand, five hundred sixty-one".