21801084 has 48 divisors (see below), whose sum is σ = 52164000. Its totient is φ = 7085056.

The previous prime is 21801071. The next prime is 21801097. The reversal of 21801084 is 48010812.

It is an interprime number because it is at equal distance from previous prime (21801071) and next prime (21801097).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146242 + ... + 146390.

It is an arithmetic number, because the mean of its divisors is an integer number (1086750).

Almost surely, 2^21801084 is an apocalyptic number.

It is an amenable number.

21801084 is an abundant number, since it is smaller than the sum of its proper divisors (30362916).

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

21801084 is a wasteful number, since it uses less digits than its factorization.

21801084 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 380 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 21801084 is about 4669.1630941744. The cubic root of 21801084 is about 279.3568742901.

Adding to 21801084 its reverse (48010812), we get a palindrome (69811896).

The spelling of 21801084 in words is "twenty-one million, eight hundred one thousand, eighty-four".