2161220947 has 2 divisors, whose sum is σ = 2161220948. Its totient is φ = 2161220946.

The previous prime is 2161220879. The next prime is 2161220951. The reversal of 2161220947 is 7490221612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2161220947 - 2¹⁵ = 2161188179 is a prime.

It is not a weakly prime, because it can be changed into another prime (2161220977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080610473 + 1080610474.

It is an arithmetic number, because the mean of its divisors is an integer number (1080610474).

Almost surely, 2^2161220947 is an apocalyptic number.

2161220947 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161220947 is an equidigital number, since it uses as much as digits as its factorization.

2161220947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 2161220947 is about 46488.9335971476. The cubic root of 2161220947 is about 1292.9043283806.

The spelling of 2161220947 in words is "two billion, one hundred sixty-one million, two hundred twenty thousand, nine hundred forty-seven".