21036340 has 24 divisors (see below), whose sum is σ = 47575080. Its totient is φ = 7767168.

The previous prime is 21036311. The next prime is 21036341. The reversal of 21036340 is 4363012.

It can be written as a sum of positive squares in 4 ways, for example, as 41616 + 20994724 = 204^2 + 4582^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036341) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40195 + ... + 40714.

It is an arithmetic number, because the mean of its divisors is an integer number (1982295).

Almost surely, 2^21036340 is an apocalyptic number.

21036340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21036340 is an abundant number, since it is smaller than the sum of its proper divisors (26538740).

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

21036340 is a wasteful number, since it uses less digits than its factorization.

21036340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80931 (or 80929 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 21036340 is about 4586.5390001612. The cubic root of 21036340 is about 276.0514676825.

Adding to 21036340 its reverse (4363012), we get a palindrome (25399352).

The spelling of 21036340 in words is "twenty-one million, thirty-six thousand, three hundred forty".