21012542 has 8 divisors (see below), whose sum is σ = 31615032. Its totient is φ = 10474200.

The previous prime is 21012533. The next prime is 21012569. The reversal of 21012542 is 24521012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21012542.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15209 + ... + 16532.

It is an arithmetic number, because the mean of its divisors is an integer number (3951879).

Almost surely, 2^21012542 is an apocalyptic number.

21012542 is a deficient number, since it is larger than the sum of its proper divisors (10602490).

21012542 is a wasteful number, since it uses less digits than its factorization.

21012542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32074.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21012542 is about 4583.9439350847. The cubic root of 21012542 is about 275.9473311947.

Adding to 21012542 its reverse (24521012), we get a palindrome (45533554).

The spelling of 21012542 in words is "twenty-one million, twelve thousand, five hundred forty-two".