21340620 has 72 divisors (see below), whose sum is σ = 73985184. Its totient is φ = 4877568.

The previous prime is 21340603. The next prime is 21340633. The reversal of 21340620 is 2604312.

It is a happy number.

21340620 is a `hidden beast` number, since 2 + 1 + 3 + 40 + 620 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21340593 and 21340602.

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 23 ways as a sum of consecutive naturals, for example, 7209 + ... + 9728.

It is an arithmetic number, because the mean of its divisors is an integer number (1027572).

Almost surely, 2^21340620 is an apocalyptic number.

21340620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21340620 is an abundant number, since it is smaller than the sum of its proper divisors (52644564).

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

21340620 is a wasteful number, since it uses less digits than its factorization.

21340620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16959 (or 16954 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21340620 is about 4619.5908909773. The cubic root of 21340620 is about 277.3760829738.

Adding to 21340620 its reverse (2604312), we get a palindrome (23944932).

The spelling of 21340620 in words is "twenty-one million, three hundred forty thousand, six hundred twenty".