2211991761 has 72 divisors (see below), whose sum is σ = 3676948704. Its totient is φ = 1178997120.

The previous prime is 2211991759. The next prime is 2211991777. The reversal of 2211991761 is 1671991122.

It is not a de Polignac number, because 2211991761 - 2¹ = 2211991759 is a prime.

It is a super-2 number, since 2×2211991761² = 9785815101463762242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2211991741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3873606 + ... + 3874176.

It is an arithmetic number, because the mean of its divisors is an integer number (51068732).

Almost surely, 2^2211991761 is an apocalyptic number.

2211991761 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2211991761 is a deficient number, since it is larger than the sum of its proper divisors (1464956943).

2211991761 is a wasteful number, since it uses less digits than its factorization.

2211991761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699 (or 673 counting only the distinct ones).

The product of its digits is 13608, while the sum is 39.

The square root of 2211991761 is about 47031.8164756583. The cubic root of 2211991761 is about 1302.9502543821.

The spelling of 2211991761 in words is "two billion, two hundred eleven million, nine hundred ninety-one thousand, seven hundred sixty-one".