21025255 has 8 divisors (see below), whose sum is σ = 25260624. Its totient is φ = 16800000.

The previous prime is 21025217. The next prime is 21025273. The reversal of 21025255 is 55252012.

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

It is not a de Polignac number, because 21025255 - 2⁷ = 21025127 is a prime.

It is a super-2 number, since 2×21025255² = 884122695630050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3255 + ... + 7255.

It is an arithmetic number, because the mean of its divisors is an integer number (3157578).

Almost surely, 2^21025255 is an apocalyptic number.

21025255 is a deficient number, since it is larger than the sum of its proper divisors (4235369).

21025255 is a wasteful number, since it uses less digits than its factorization.

21025255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5057.

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21025255 is about 4585.3304133944. The cubic root of 21025255 is about 276.0029711575.

Adding to 21025255 its reverse (55252012), we get a palindrome (76277267).

The spelling of 21025255 in words is "twenty-one million, twenty-five thousand, two hundred fifty-five".