2561991362 has 18 divisors (see below), whose sum is σ = 4471287993. Its totient is φ = 1097781552.

The previous prime is 2561991353. The next prime is 2561991371. The reversal of 2561991362 is 2631991652.

It is an interprime number because it is at equal distance from previous prime (2561991353) and next prime (2561991371).

It can be written as a sum of positive squares in 2 ways, for example, as 1532800801 + 1029190561 = 39151^2 + 32081^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=35791.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 498518 + ... + 503630.

Almost surely, 2^2561991362 is an apocalyptic number.

2561991362 is a deficient number, since it is larger than the sum of its proper divisors (1909296631).

2561991362 is an frugal number, since it uses more digits than its factorization.

2561991362 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10242 (or 5122 counting only the distinct ones).

The product of its digits is 174960, while the sum is 44.

The square root of 2561991362 is about 50616.1176108954. The cubic root of 2561991362 is about 1368.3353717754.

The spelling of 2561991362 in words is "two billion, five hundred sixty-one million, nine hundred ninety-one thousand, three hundred sixty-two".