21302040 has 64 divisors (see below), whose sum is σ = 67276800. Its totient is φ = 5380992.

The previous prime is 21302027. The next prime is 21302051. The reversal of 21302040 is 4020312.

It is a Harshad number since it is a multiple of its sum of digits (12).

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, 2392 + ... + 6951.

It is an arithmetic number, because the mean of its divisors is an integer number (1051200).

Almost surely, 2^21302040 is an apocalyptic number.

21302040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21302040 is an abundant number, since it is smaller than the sum of its proper divisors (45974760).

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

21302040 is a wasteful number, since it uses less digits than its factorization.

21302040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9376 (or 9372 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21302040 is about 4615.4133076031. The cubic root of 21302040 is about 277.2088334693.

Adding to 21302040 its reverse (4020312), we get a palindrome (25322352).

The spelling of 21302040 in words is "twenty-one million, three hundred two thousand, forty".