25728215 has 4 divisors (see below), whose sum is σ = 30873864. Its totient is φ = 20582568.

The previous prime is 25728211. The next prime is 25728221. The reversal of 25728215 is 51282752.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 25728215 - 2² = 25728211 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25728211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2572817 + ... + 2572826.

It is an arithmetic number, because the mean of its divisors is an integer number (7718466).

Almost surely, 2^25728215 is an apocalyptic number.

25728215 is a deficient number, since it is larger than the sum of its proper divisors (5145649).

25728215 is an equidigital number, since it uses as much as digits as its factorization.

25728215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5145648.

The product of its digits is 11200, while the sum is 32.

The square root of 25728215 is about 5072.2987885179. The cubic root of 25728215 is about 295.2137300124.

The spelling of 25728215 in words is "twenty-five million, seven hundred twenty-eight thousand, two hundred fifteen".