25555999 has 6 divisors (see below), whose sum is σ = 29728464. Its totient is φ = 21905100.

The previous prime is 25555993. The next prime is 25556021. The reversal of 25555999 is 99955552.

It is not a de Polignac number, because 25555999 - 2¹³ = 25547807 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 521551 = 25555999 / (2 + 5 + 5 + 5 + 5 + 9 + 9 + 9).

It is a Duffinian number.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25555993) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 260727 + ... + 260824.

It is an arithmetic number, because the mean of its divisors is an integer number (4954744).

Almost surely, 2^25555999 is an apocalyptic number.

25555999 is a deficient number, since it is larger than the sum of its proper divisors (4172465).

25555999 is an equidigital number, since it uses as much as digits as its factorization.

25555999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521565 (or 521558 counting only the distinct ones).

The product of its digits is 911250, while the sum is 49.

The square root of 25555999 is about 5055.2941556353. The cubic root of 25555999 is about 294.5535677753.

The spelling of 25555999 in words is "twenty-five million, five hundred fifty-five thousand, nine hundred ninety-nine".