21725030 has 16 divisors (see below), whose sum is σ = 39342240. Its totient is φ = 8637312.

The previous prime is 21725027. The next prime is 21725047. The reversal of 21725030 is 3052712.

It is a junction number, because it is equal to n+sod(n) for n = 21724993 and 21725011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4835 + ... + 8174.

It is an arithmetic number, because the mean of its divisors is an integer number (2458890).

Almost surely, 2^21725030 is an apocalyptic number.

21725030 is a deficient number, since it is larger than the sum of its proper divisors (17617210).

21725030 is a wasteful number, since it uses less digits than its factorization.

21725030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13183.

The product of its (nonzero) digits is 420, while the sum is 20.

The square root of 21725030 is about 4661.0116927551. The cubic root of 21725030 is about 279.0316463976.

Adding to 21725030 its reverse (3052712), we get a palindrome (24777742).

The spelling of 21725030 in words is "twenty-one million, seven hundred twenty-five thousand, thirty".