2601656978 has 6 divisors (see below), whose sum is σ = 3902593671. Its totient is φ = 1300792422.

The previous prime is 2601656971. The next prime is 2601657011. The reversal of 2601656978 is 8796561062.

It can be written as a sum of positive squares in only one way, i.e., 1300828489 + 1300828489 = 36067^2 + 36067^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=36067.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2601656971) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 54101 + ... + 90167.

Almost surely, 2^2601656978 is an apocalyptic number.

2601656978 is a deficient number, since it is larger than the sum of its proper divisors (1300936693).

2601656978 is an frugal number, since it uses more digits than its factorization.

2601656978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72136 (or 36069 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 50.

The square root of 2601656978 is about 51006.4405541104. The cubic root of 2601656978 is about 1375.3609151527.

Multiplying 2601656978 by its sum of digits (50), we get a square (130082848900 = 360670²).

The spelling of 2601656978 in words is "two billion, six hundred one million, six hundred fifty-six thousand, nine hundred seventy-eight".