21011490 has 96 divisors (see below), whose sum is σ = 59844096. Its totient is φ = 5091840.

The previous prime is 21011453. The next prime is 21011503. The reversal of 21011490 is 9411012.

It is a Harshad number since it is a multiple of its sum of digits (18).

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, 47209 + ... + 47651.

It is an arithmetic number, because the mean of its divisors is an integer number (623376).

Almost surely, 2^21011490 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21011490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29922048).

21011490 is an abundant number, since it is smaller than the sum of its proper divisors (38832606).

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

21011490 is a wasteful number, since it uses less digits than its factorization.

21011490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504 (or 501 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21011490 is about 4583.8291852991. The cubic root of 21011490 is about 275.9427259858.

The spelling of 21011490 in words is "twenty-one million, eleven thousand, four hundred ninety".