21626390 has 8 divisors (see below), whose sum is σ = 38927520. Its totient is φ = 8650552.

The previous prime is 21626369. The next prime is 21626399. The reversal of 21626390 is 9362612.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21626399) 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, 1081310 + ... + 1081329.

It is an arithmetic number, because the mean of its divisors is an integer number (4865940).

Almost surely, 2^21626390 is an apocalyptic number.

21626390 is a deficient number, since it is larger than the sum of its proper divisors (17301130).

21626390 is a wasteful number, since it uses less digits than its factorization.

21626390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2162646.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 21626390 is about 4650.4182607589. The cubic root of 21626390 is about 278.6087019409.

The spelling of 21626390 in words is "twenty-one million, six hundred twenty-six thousand, three hundred ninety".