21053042 has 4 divisors (see below), whose sum is σ = 31579566. Its totient is φ = 10526520.

The previous prime is 21053041. The next prime is 21053051. The reversal of 21053042 is 24035012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20349121 + 703921 = 4511^2 + 839^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21053042.

It is not an unprimeable number, because it can be changed into a prime (21053041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5263259 + ... + 5263262.

Almost surely, 2^21053042 is an apocalyptic number.

21053042 is a deficient number, since it is larger than the sum of its proper divisors (10526524).

21053042 is a wasteful number, since it uses less digits than its factorization.

21053042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10526523.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21053042 is about 4588.3594017906. The cubic root of 21053042 is about 276.1245062425.

Adding to 21053042 its reverse (24035012), we get a palindrome (45088054).

The spelling of 21053042 in words is "twenty-one million, fifty-three thousand, forty-two".