21738190 has 8 divisors (see below), whose sum is σ = 39128760. Its totient is φ = 8695272.

The previous prime is 21738187. The next prime is 21738191. The reversal of 21738190 is 9183712.

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

It is a super-2 number, since 2×21738190² = 945097808952200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738191) 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, 1086900 + ... + 1086919.

It is an arithmetic number, because the mean of its divisors is an integer number (4891095).

Almost surely, 2^21738190 is an apocalyptic number.

21738190 is a deficient number, since it is larger than the sum of its proper divisors (17390570).

21738190 is a wasteful number, since it uses less digits than its factorization.

21738190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2173826.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21738190 is about 4662.4231897158. The cubic root of 21738190 is about 279.0879764351.

The spelling of 21738190 in words is "twenty-one million, seven hundred thirty-eight thousand, one hundred ninety".