21813370 has 8 divisors (see below), whose sum is σ = 39264084. Its totient is φ = 8725344.

The previous prime is 21813343. The next prime is 21813371. The reversal of 21813370 is 7331812.

It can be written as a sum of positive squares in 2 ways, for example, as 21261321 + 552049 = 4611^2 + 743^2 .

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

It is a super-2 number, since 2×21813370² = 951646221513800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21813371) 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 3 ways as a sum of consecutive naturals, for example, 1090659 + ... + 1090678.

Almost surely, 2^21813370 is an apocalyptic number.

21813370 is a deficient number, since it is larger than the sum of its proper divisors (17450714).

21813370 is a wasteful number, since it uses less digits than its factorization.

21813370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2181344.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21813370 is about 4670.4785622032. The cubic root of 21813370 is about 279.4093416204.

The spelling of 21813370 in words is "twenty-one million, eight hundred thirteen thousand, three hundred seventy".