21340556 has 24 divisors (see below), whose sum is σ = 38952144. Its totient is φ = 10221120.

The previous prime is 21340547. The next prime is 21340567. The reversal of 21340556 is 65504312.

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, 7946 + ... + 10286.

It is an arithmetic number, because the mean of its divisors is an integer number (1623006).

Almost surely, 2^21340556 is an apocalyptic number.

It is an amenable number.

21340556 is a deficient number, since it is larger than the sum of its proper divisors (17611588).

21340556 is a wasteful number, since it uses less digits than its factorization.

21340556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2441 (or 2439 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21340556 is about 4619.5839639517. The cubic root of 21340556 is about 277.3758056922.

Adding to 21340556 its reverse (65504312), we get a palindrome (86844868).

It can be divided in two parts, 2134055 and 6, that multiplied together give a triangular number (12804330 = T₅₀₆₀).

The spelling of 21340556 in words is "twenty-one million, three hundred forty thousand, five hundred fifty-six".