21281190 has 96 divisors (see below), whose sum is σ = 61461504. Its totient is φ = 4697280.

The previous prime is 21281153. The next prime is 21281201. The reversal of 21281190 is 9118212.

It is a super-2 number, since 2×21281190² = 905778095632200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21281190.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 45337 + ... + 45803.

It is an arithmetic number, because the mean of its divisors is an integer number (640224).

Almost surely, 2^21281190 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21281190, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30730752).

21281190 is an abundant number, since it is smaller than the sum of its proper divisors (40180314).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21281190 is a wasteful number, since it uses less digits than its factorization.

21281190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 515 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 21281190 is about 4613.1540186731. The cubic root of 21281190 is about 277.1183618381.

The spelling of 21281190 in words is "twenty-one million, two hundred eighty-one thousand, one hundred ninety".