21526340 has 24 divisors (see below), whose sum is σ = 49315392. Its totient is φ = 7827680.

The previous prime is 21526339. The next prime is 21526357. The reversal of 21526340 is 4362512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48704 + ... + 49143.

It is an arithmetic number, because the mean of its divisors is an integer number (2054808).

Almost surely, 2^21526340 is an apocalyptic number.

21526340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21526340 is an abundant number, since it is smaller than the sum of its proper divisors (27789052).

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

21526340 is a wasteful number, since it uses less digits than its factorization.

21526340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97867 (or 97865 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21526340 is about 4639.6486935974. The cubic root of 21526340 is about 278.1783959258.

Adding to 21526340 its reverse (4362512), we get a palindrome (25888852).

The spelling of 21526340 in words is "twenty-one million, five hundred twenty-six thousand, three hundred forty".