21342556 has 12 divisors (see below), whose sum is σ = 37769760. Its totient is φ = 10551200.

The previous prime is 21342553. The next prime is 21342557. The reversal of 21342556 is 65524312.

It is a super-2 number, since 2×21342556² = 911009393226272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21342553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29620 + ... + 30331.

It is an arithmetic number, because the mean of its divisors is an integer number (3147480).

Almost surely, 2^21342556 is an apocalyptic number.

It is an amenable number.

21342556 is a deficient number, since it is larger than the sum of its proper divisors (16427204).

21342556 is a wasteful number, since it uses less digits than its factorization.

21342556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60044 (or 60042 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 21342556 is about 4619.8004285900. The cubic root of 21342556 is about 277.3844704818.

Adding to 21342556 its reverse (65524312), we get a palindrome (86866868).

The spelling of 21342556 in words is "twenty-one million, three hundred forty-two thousand, five hundred fifty-six".