21000242 has 16 divisors (see below), whose sum is σ = 32970240. Its totient is φ = 10031956.

The previous prime is 21000233. The next prime is 21000251. The reversal of 21000242 is 24200012.

It is an interprime number because it is at equal distance from previous prime (21000233) and next prime (21000251).

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, 23903 + ... + 24765.

It is an arithmetic number, because the mean of its divisors is an integer number (2060640).

Almost surely, 2^21000242 is an apocalyptic number.

21000242 is a deficient number, since it is larger than the sum of its proper divisors (11969998).

21000242 is an frugal number, since it uses more digits than its factorization.

21000242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 934 (or 888 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 21000242 is about 4582.6020992445. The cubic root of 21000242 is about 275.8934774113.

Adding to 21000242 its reverse (24200012), we get a palindrome (45200254).

The spelling of 21000242 in words is "twenty-one million, two hundred forty-two", and thus it is an aban number.