21486740 has 48 divisors (see below), whose sum is σ = 49762944. Its totient is φ = 7728000.

The previous prime is 21486737. The next prime is 21486779. The reversal of 21486740 is 4768412.

It is a junction number, because it is equal to n+sod(n) for n = 21486697 and 21486706.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21737 + ... + 22703.

It is an arithmetic number, because the mean of its divisors is an integer number (1036728).

Almost surely, 2^21486740 is an apocalyptic number.

21486740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21486740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24881472).

21486740 is an abundant number, since it is smaller than the sum of its proper divisors (28276204).

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

21486740 is a wasteful number, since it uses less digits than its factorization.

21486740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1088 (or 1086 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 21486740 is about 4635.3791646423. The cubic root of 21486740 is about 278.0077116022.

It can be divided in two parts, 2148 and 6740, that added together give a palindrome (8888).

The spelling of 21486740 in words is "twenty-one million, four hundred eighty-six thousand, seven hundred forty".