21051542 has 16 divisors (see below), whose sum is σ = 34515072. Its totient is φ = 9586560.

The previous prime is 21051529. The next prime is 21051599. The reversal of 21051542 is 24515012.

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, 8933 + ... + 11040.

It is an arithmetic number, because the mean of its divisors is an integer number (2157192).

Almost surely, 2^21051542 is an apocalyptic number.

21051542 is a deficient number, since it is larger than the sum of its proper divisors (13463530).

21051542 is a wasteful number, since it uses less digits than its factorization.

21051542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20023.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21051542 is about 4588.1959417619. The cubic root of 21051542 is about 276.1179482575.

Adding to 21051542 its reverse (24515012), we get a palindrome (45566554).

The spelling of 21051542 in words is "twenty-one million, fifty-one thousand, five hundred forty-two".