21126542 has 16 divisors (see below), whose sum is σ = 32460912. Its totient is φ = 10308480.

The previous prime is 21126533. The next prime is 21126551. The reversal of 21126542 is 24562112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21126533) and next prime (21126551).

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, 25133 + ... + 25959.

It is an arithmetic number, because the mean of its divisors is an integer number (2028807).

Almost surely, 2^21126542 is an apocalyptic number.

21126542 is a deficient number, since it is larger than the sum of its proper divisors (11334370).

21126542 is a wasteful number, since it uses less digits than its factorization.

21126542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1123.

The product of its digits is 960, while the sum is 23.

The square root of 21126542 is about 4596.3618221372. The cubic root of 21126542 is about 276.4454666511.

Adding to 21126542 its reverse (24562112), we get a palindrome (45688654).

The spelling of 21126542 in words is "twenty-one million, one hundred twenty-six thousand, five hundred forty-two".