21226990 has 16 divisors (see below), whose sum is σ = 40219920. Its totient is φ = 8043840.

The previous prime is 21226969. The next prime is 21227023. The reversal of 21226990 is 9962212.

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, 55671 + ... + 56050.

It is an arithmetic number, because the mean of its divisors is an integer number (2513745).

Almost surely, 2^21226990 is an apocalyptic number.

21226990 is a deficient number, since it is larger than the sum of its proper divisors (18992930).

21226990 is a wasteful number, since it uses less digits than its factorization.

21226990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111747.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21226990 is about 4607.2757677395. The cubic root of 21226990 is about 276.8829021927.

The spelling of 21226990 in words is "twenty-one million, two hundred twenty-six thousand, nine hundred ninety".