21002275 has 24 divisors (see below), whose sum is σ = 30466304. Its totient is φ = 14061600.

The previous prime is 21002269. The next prime is 21002287. The reversal of 21002275 is 57220012.

It is not a de Polignac number, because 21002275 - 2⁹ = 21001763 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6130 + ... + 8920.

Almost surely, 2^21002275 is an apocalyptic number.

21002275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21002275 is a deficient number, since it is larger than the sum of its proper divisors (9464029).

21002275 is a wasteful number, since it uses less digits than its factorization.

21002275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2851 (or 2846 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21002275 is about 4582.8239110836. The cubic root of 21002275 is about 275.9023800601.

Adding to 21002275 its reverse (57220012), we get a palindrome (78222287).

The spelling of 21002275 in words is "twenty-one million, two thousand, two hundred seventy-five".