21485990 has 8 divisors (see below), whose sum is σ = 38674800. Its totient is φ = 8594392.

The previous prime is 21485957. The next prime is 21485993. The reversal of 21485990 is 9958412.

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 (21485993) 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, 1074290 + ... + 1074309.

It is an arithmetic number, because the mean of its divisors is an integer number (4834350).

Almost surely, 2^21485990 is an apocalyptic number.

21485990 is a deficient number, since it is larger than the sum of its proper divisors (17188810).

21485990 is a wasteful number, since it uses less digits than its factorization.

21485990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2148606.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 21485990 is about 4635.2982644054. The cubic root of 21485990 is about 278.0044769218.

The spelling of 21485990 in words is "twenty-one million, four hundred eighty-five thousand, nine hundred ninety".