21797725 has 12 divisors (see below), whose sum is σ = 27185760. Its totient is φ = 17337200.

The previous prime is 21797701. The next prime is 21797729. The reversal of 21797725 is 52779712.

It is a happy number.

It is not a de Polignac number, because 21797725 - 2⁷ = 21797597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797729) 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, 2040 + ... + 6910.

It is an arithmetic number, because the mean of its divisors is an integer number (2265480).

Almost surely, 2^21797725 is an apocalyptic number.

21797725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21797725 is a deficient number, since it is larger than the sum of its proper divisors (5388035).

21797725 is a wasteful number, since it uses less digits than its factorization.

21797725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5060 (or 5055 counting only the distinct ones).

The product of its digits is 61740, while the sum is 40.

The square root of 21797725 is about 4668.8033798823. The cubic root of 21797725 is about 279.3425262583.

It can be divided in two parts, 21797 and 725, that added together give a palindrome (22522).

The spelling of 21797725 in words is "twenty-one million, seven hundred ninety-seven thousand, seven hundred twenty-five".