21701825 has 6 divisors (see below), whose sum is σ = 26910294. Its totient is φ = 17361440.

The previous prime is 21701821. The next prime is 21701837. The reversal of 21701825 is 52810712.

It can be written as a sum of positive squares in 3 ways, for example, as 6012304 + 15689521 = 2452^2 + 3961^2 .

It is not a de Polignac number, because 21701825 - 2² = 21701821 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21701794 and 21701803.

It is not an unprimeable number, because it can be changed into a prime (21701821) 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, 434012 + ... + 434061.

It is an arithmetic number, because the mean of its divisors is an integer number (4485049).

Almost surely, 2^21701825 is an apocalyptic number.

21701825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21701825 is a deficient number, since it is larger than the sum of its proper divisors (5208469).

21701825 is an equidigital number, since it uses as much as digits as its factorization.

21701825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 868083 (or 868078 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21701825 is about 4658.5217612457. The cubic root of 21701825 is about 278.9322643168.

The spelling of 21701825 in words is "twenty-one million, seven hundred one thousand, eight hundred twenty-five".