21830288 has 20 divisors (see below), whose sum is σ = 42584700. Its totient is φ = 10840704.

The previous prime is 21830287. The next prime is 21830311. The reversal of 21830288 is 88203812.

It can be written as a sum of positive squares in 2 ways, for example, as 2715904 + 19114384 = 1648^2 + 4372^2 .

It is a super-2 number, since 2×21830288² = 953122948325888, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21830287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2195 + ... + 6962.

It is an arithmetic number, because the mean of its divisors is an integer number (2129235).

Almost surely, 2^21830288 is an apocalyptic number.

It is an amenable number.

21830288 is a deficient number, since it is larger than the sum of its proper divisors (20754412).

21830288 is a wasteful number, since it uses less digits than its factorization.

21830288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9314 (or 9308 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 32.

The square root of 21830288 is about 4672.2893746000. The cubic root of 21830288 is about 279.4815576619.

The spelling of 21830288 in words is "twenty-one million, eight hundred thirty thousand, two hundred eighty-eight".