21262851 has 8 divisors (see below), whose sum is σ = 31500560. Its totient is φ = 14175216.

The previous prime is 21262849. The next prime is 21262853. The reversal of 21262851 is 15826212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21262849) and next prime (21262853).

It is not a de Polignac number, because 21262851 - 2¹ = 21262849 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 787513 = 21262851 / (2 + 1 + 2 + 6 + 2 + 8 + 5 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21262853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 393730 + ... + 393783.

It is an arithmetic number, because the mean of its divisors is an integer number (3937570).

Almost surely, 2^21262851 is an apocalyptic number.

21262851 is a deficient number, since it is larger than the sum of its proper divisors (10237709).

21262851 is an equidigital number, since it uses as much as digits as its factorization.

21262851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 787522 (or 787516 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 21262851 is about 4611.1659046276. The cubic root of 21262851 is about 277.0387369964.

The spelling of 21262851 in words is "twenty-one million, two hundred sixty-two thousand, eight hundred fifty-one".