2161220977 has 2 divisors, whose sum is σ = 2161220978. Its totient is φ = 2161220976.

The previous prime is 2161220951. The next prime is 2161221061. The reversal of 2161220977 is 7790221612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2143319616 + 17901361 = 46296^2 + 4231^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161220977 - 2¹⁵ = 2161188209 is a prime.

It is a super-2 number, since 2×2161220977² = 9341752222849669058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2161220947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080610488 + 1080610489.

It is an arithmetic number, because the mean of its divisors is an integer number (1080610489).

Almost surely, 2^2161220977 is an apocalyptic number.

It is an amenable number.

2161220977 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161220977 is an equidigital number, since it uses as much as digits as its factorization.

2161220977 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 2161220977 is about 46488.9339198050. The cubic root of 2161220977 is about 1292.9043343629.

The spelling of 2161220977 in words is "two billion, one hundred sixty-one million, two hundred twenty thousand, nine hundred seventy-seven".