21340660 has 24 divisors (see below), whose sum is σ = 48890016. Its totient is φ = 7760160.

The previous prime is 21340651. The next prime is 21340663. The reversal of 21340660 is 6604312.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340663) 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, 48282 + ... + 48721.

It is an arithmetic number, because the mean of its divisors is an integer number (2037084).

Almost surely, 2^21340660 is an apocalyptic number.

21340660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21340660 is an abundant number, since it is smaller than the sum of its proper divisors (27549356).

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

21340660 is a wasteful number, since it uses less digits than its factorization.

21340660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97023 (or 97021 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 21340660 is about 4619.5952203629. The cubic root of 21340660 is about 277.3762562746.

Adding to 21340660 its reverse (6604312), we get a palindrome (27944972).

The spelling of 21340660 in words is "twenty-one million, three hundred forty thousand, six hundred sixty".