21343540 has 24 divisors (see below), whose sum is σ = 46771200. Its totient is φ = 8166048.

The previous prime is 21343519. The next prime is 21343579. The reversal of 21343540 is 4534312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22740 + ... + 23659.

It is an arithmetic number, because the mean of its divisors is an integer number (1948800).

Almost surely, 2^21343540 is an apocalyptic number.

21343540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21343540 is an abundant number, since it is smaller than the sum of its proper divisors (25427660).

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

21343540 is a wasteful number, since it uses less digits than its factorization.

21343540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46431 (or 46429 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 21343540 is about 4619.9069254694. The cubic root of 21343540 is about 277.3887333596.

Adding to 21343540 its reverse (4534312), we get a palindrome (25877852).

The spelling of 21343540 in words is "twenty-one million, three hundred forty-three thousand, five hundred forty".