25771561 has 2 divisors, whose sum is σ = 25771562. Its totient is φ = 25771560.

The previous prime is 25771549. The next prime is 25771567. The reversal of 25771561 is 16517752.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22278400 + 3493161 = 4720^2 + 1869^2 .

It is a cyclic number.

It is not a de Polignac number, because 25771561 - 2¹³ = 25763369 is a prime.

It is not a weakly prime, because it can be changed into another prime (25771567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12885780 + 12885781.

It is an arithmetic number, because the mean of its divisors is an integer number (12885781).

Almost surely, 2^25771561 is an apocalyptic number.

It is an amenable number.

25771561 is a deficient number, since it is larger than the sum of its proper divisors (1).

25771561 is an equidigital number, since it uses as much as digits as its factorization.

25771561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14700, while the sum is 34.

The square root of 25771561 is about 5076.5698064737. The cubic root of 25771561 is about 295.3794255958.

The spelling of 25771561 in words is "twenty-five million, seven hundred seventy-one thousand, five hundred sixty-one".