21751025 has 12 divisors (see below), whose sum is σ = 27236352. Its totient is φ = 17229840.

The previous prime is 21751021. The next prime is 21751027. The reversal of 21751025 is 52015712.

It is a happy number.

It is not a de Polignac number, because 21751025 - 2² = 21751021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21751021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1649 + ... + 6798.

It is an arithmetic number, because the mean of its divisors is an integer number (2269696).

Almost surely, 2^21751025 is an apocalyptic number.

21751025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21751025 is a deficient number, since it is larger than the sum of its proper divisors (5485327).

21751025 is a wasteful number, since it uses less digits than its factorization.

21751025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8560 (or 8555 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 21751025 is about 4663.7994167846. The cubic root of 21751025 is about 279.1428934485.

Adding to 21751025 its reverse (52015712), we get a palindrome (73766737).

The spelling of 21751025 in words is "twenty-one million, seven hundred fifty-one thousand, twenty-five".