2651664561 has 64 divisors (see below), whose sum is σ = 4569600000. Its totient is φ = 1330027776.

The previous prime is 2651664557. The next prime is 2651664563. The reversal of 2651664561 is 1654661562.

It is not a de Polignac number, because 2651664561 - 2² = 2651664557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2651664563) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 527940 + ... + 532938.

It is an arithmetic number, because the mean of its divisors is an integer number (71400000).

Almost surely, 2^2651664561 is an apocalyptic number.

2651664561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2651664561 is a deficient number, since it is larger than the sum of its proper divisors (1917935439).

2651664561 is a wasteful number, since it uses less digits than its factorization.

2651664561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5118.

The product of its digits is 259200, while the sum is 42.

The square root of 2651664561 is about 51494.3158125244. The cubic root of 2651664561 is about 1384.1171870614.

Subtracting from 2651664561 its reverse (1654661562), we obtain a cube (997002999 = 999³).

The spelling of 2651664561 in words is "two billion, six hundred fifty-one million, six hundred sixty-four thousand, five hundred sixty-one".