21438190 has 16 divisors (see below), whose sum is σ = 40858992. Its totient is φ = 8070784.

The previous prime is 21438187. The next prime is 21438211. The reversal of 21438190 is 9183412.

It is a happy number.

It is a super-2 number, since 2×21438190² = 919191980952200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62884 + ... + 63223.

It is an arithmetic number, because the mean of its divisors is an integer number (2553687).

Almost surely, 2^21438190 is an apocalyptic number.

21438190 is a deficient number, since it is larger than the sum of its proper divisors (19420802).

21438190 is a wasteful number, since it uses less digits than its factorization.

21438190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126131.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 21438190 is about 4630.1393067596. The cubic root of 21438190 is about 277.7981644889.

The spelling of 21438190 in words is "twenty-one million, four hundred thirty-eight thousand, one hundred ninety".