25781947 has 2 divisors, whose sum is σ = 25781948. Its totient is φ = 25781946.

The previous prime is 25781929. The next prime is 25781953. The reversal of 25781947 is 74918752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25781947 - 2¹¹ = 25779899 is a prime.

It is a super-2 number, since 2×25781947² = 1329417582221618, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (25781447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12890973 + 12890974.

It is an arithmetic number, because the mean of its divisors is an integer number (12890974).

Almost surely, 2^25781947 is an apocalyptic number.

25781947 is a deficient number, since it is larger than the sum of its proper divisors (1).

25781947 is an equidigital number, since it uses as much as digits as its factorization.

25781947 is an evil number, because the sum of its binary digits is even.

The product of its digits is 141120, while the sum is 43.

The square root of 25781947 is about 5077.5926382490. The cubic root of 25781947 is about 295.4190998023.

The spelling of 25781947 in words is "twenty-five million, seven hundred eighty-one thousand, nine hundred forty-seven".