999220961 has 2 divisors, whose sum is σ = 999220962. Its totient is φ = 999220960.

The previous prime is 999220939. The next prime is 999220967. The reversal of 999220961 is 169022999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 952092736 + 47128225 = 30856^2 + 6865^2 .

It is a cyclic number.

It is not a de Polignac number, because 999220961 - 2²² = 995026657 is a prime.

It is not a weakly prime, because it can be changed into another prime (999220967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499610480 + 499610481.

It is an arithmetic number, because the mean of its divisors is an integer number (499610481).

Almost surely, 2^999220961 is an apocalyptic number.

It is an amenable number.

999220961 is a deficient number, since it is larger than the sum of its proper divisors (1).

999220961 is an equidigital number, since it uses as much as digits as its factorization.

999220961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 157464, while the sum is 47.

The square root of 999220961 is about 31610.4565136285. The cubic root of 999220961 is about 999.7402528706.

The spelling of 999220961 in words is "nine hundred ninety-nine million, two hundred twenty thousand, nine hundred sixty-one".