21970725 has 24 divisors (see below), whose sum is σ = 41515200. Its totient is φ = 10043520.

The previous prime is 21970717. The next prime is 21970747. The reversal of 21970725 is 52707912.

It is not a de Polignac number, because 21970725 - 2³ = 21970717 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20400 + ... + 21449.

It is an arithmetic number, because the mean of its divisors is an integer number (1729800).

Almost surely, 2^21970725 is an apocalyptic number.

21970725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21970725 is a deficient number, since it is larger than the sum of its proper divisors (19544475).

21970725 is a wasteful number, since it uses less digits than its factorization.

21970725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41869 (or 41864 counting only the distinct ones).

The product of its (nonzero) digits is 8820, while the sum is 33.

The square root of 21970725 is about 4687.2939954733. The cubic root of 21970725 is about 280.0795904694.

It can be divided in two parts, 21 and 970725, that multiplied together give a square (20385225 = 4515²).

The spelling of 21970725 in words is "twenty-one million, nine hundred seventy thousand, seven hundred twenty-five".