21800890 has 8 divisors (see below), whose sum is σ = 39241620. Its totient is φ = 8720352.

The previous prime is 21800873. The next prime is 21800897. The reversal of 21800890 is 9800812.

It can be written as a sum of positive squares in 2 ways, for example, as 21242881 + 558009 = 4609^2 + 747^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21800897) 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, 1090035 + ... + 1090054.

Almost surely, 2^21800890 is an apocalyptic number.

21800890 is a deficient number, since it is larger than the sum of its proper divisors (17440730).

21800890 is a wasteful number, since it uses less digits than its factorization.

21800890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2180096.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 21800890 is about 4669.1423195272. The cubic root of 21800890 is about 279.3560456556.

The spelling of 21800890 in words is "twenty-one million, eight hundred thousand, eight hundred ninety".