21672425 has 24 divisors (see below), whose sum is σ = 28123200. Its totient is φ = 16546880.

The previous prime is 21672421. The next prime is 21672439. The reversal of 21672425 is 52427612.

It is a happy number.

It is not a de Polignac number, because 21672425 - 2² = 21672421 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is not an unprimeable number, because it can be changed into a prime (21672421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120986 + ... + 121164.

It is an arithmetic number, because the mean of its divisors is an integer number (1171800).

Almost surely, 2^21672425 is an apocalyptic number.

21672425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21672425 is a deficient number, since it is larger than the sum of its proper divisors (6450775).

21672425 is a wasteful number, since it uses less digits than its factorization.

21672425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385 (or 380 counting only the distinct ones).

The product of its digits is 6720, while the sum is 29.

The square root of 21672425 is about 4655.3651843867. The cubic root of 21672425 is about 278.8062485777.

The spelling of 21672425 in words is "twenty-one million, six hundred seventy-two thousand, four hundred twenty-five".