21002442 has 8 divisors (see below), whose sum is σ = 42004896. Its totient is φ = 7000812.

The previous prime is 21002431. The next prime is 21002461. The reversal of 21002442 is 24420012.

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

21002442 is an admirable number.

It is a super-2 number, since 2×21002442² = 882205139926728, which contains 22 as substring.

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, 1750198 + ... + 1750209.

It is an arithmetic number, because the mean of its divisors is an integer number (5250612).

Almost surely, 2^21002442 is an apocalyptic number.

21002442 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21002442 is a wasteful number, since it uses less digits than its factorization.

21002442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3500412.

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 21002442 is about 4582.8421312544. The cubic root of 21002442 is about 275.9031113392.

Adding to 21002442 its reverse (24420012), we get a palindrome (45422454).

The spelling of 21002442 in words is "twenty-one million, two thousand, four hundred forty-two".