21856030 has 16 divisors (see below), whose sum is σ = 44961120. Its totient is φ = 7493472.

The previous prime is 21855983. The next prime is 21856031. The reversal of 21856030 is 3065812.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21855986 and 21856004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21856031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156045 + ... + 156184.

It is an arithmetic number, because the mean of its divisors is an integer number (2810070).

Almost surely, 2^21856030 is an apocalyptic number.

21856030 is an abundant number, since it is smaller than the sum of its proper divisors (23105090).

21856030 is a wasteful number, since it uses less digits than its factorization.

21856030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312243.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21856030 is about 4675.0433153074. The cubic root of 21856030 is about 279.5913682189.

The spelling of 21856030 in words is "twenty-one million, eight hundred fifty-six thousand, thirty".