21021242 has 8 divisors (see below), whose sum is σ = 34398432. Its totient is φ = 9555100.

The previous prime is 21021229. The next prime is 21021251. The reversal of 21021242 is 24212012.

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

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, 477734 + ... + 477777.

It is an arithmetic number, because the mean of its divisors is an integer number (4299804).

Almost surely, 2^21021242 is an apocalyptic number.

21021242 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21021242 is a deficient number, since it is larger than the sum of its proper divisors (13377190).

21021242 is a wasteful number, since it uses less digits than its factorization.

21021242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955524.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21021242 is about 4584.8928013641. The cubic root of 21021242 is about 275.9854102069.

Adding to 21021242 its reverse (24212012), we get a palindrome (45233254).

The spelling of 21021242 in words is "twenty-one million, twenty-one thousand, two hundred forty-two".