25556670721 has 8 divisors (see below), whose sum is σ = 25922076840. Its totient is φ = 25193645568.

The previous prime is 25556670709. The next prime is 25556670743. The reversal of 25556670721 is 12707665552.

It can be written as a sum of positive squares in 4 ways, for example, as 17751831696 + 7804839025 = 133236^2 + 88345^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25556670721 - 2¹⁹ = 25556146433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25556670781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 573616 + ... + 616561.

It is an arithmetic number, because the mean of its divisors is an integer number (3240259605).

Almost surely, 2^25556670721 is an apocalyptic number.

It is an amenable number.

25556670721 is a deficient number, since it is larger than the sum of its proper divisors (365406119).

25556670721 is a wasteful number, since it uses less digits than its factorization.

25556670721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1190483.

The product of its (nonzero) digits is 882000, while the sum is 46.

The spelling of 25556670721 in words is "twenty-five billion, five hundred fifty-six million, six hundred seventy thousand, seven hundred twenty-one".