21036042 has 24 divisors (see below), whose sum is σ = 47049600. Its totient is φ = 6785640.

The previous prime is 21036031. The next prime is 21036061. The reversal of 21036042 is 24063012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a zygodrome in base 4.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18292 + ... + 19407.

It is an arithmetic number, because the mean of its divisors is an integer number (1960400).

Almost surely, 2^21036042 is an apocalyptic number.

21036042 is an abundant number, since it is smaller than the sum of its proper divisors (26013558).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21036042 is a wasteful number, since it uses less digits than its factorization.

21036042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37738 (or 37735 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21036042 is about 4586.5065136768. The cubic root of 21036042 is about 276.0501641648.

Adding to 21036042 its reverse (24063012), we get a palindrome (45099054).

The spelling of 21036042 in words is "twenty-one million, thirty-six thousand, forty-two".