21083251 has 8 divisors (see below), whose sum is σ = 24123744. Its totient is φ = 18049920.

The previous prime is 21083239. The next prime is 21083263. The reversal of 21083251 is 15238012.

It is an interprime number because it is at equal distance from previous prime (21083239) and next prime (21083263).

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

It is not a de Polignac number, because 21083251 - 2¹³ = 21075059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21083291) 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, 8421 + ... + 10633.

It is an arithmetic number, because the mean of its divisors is an integer number (3015468).

Almost surely, 2^21083251 is an apocalyptic number.

21083251 is a deficient number, since it is larger than the sum of its proper divisors (3040493).

21083251 is a wasteful number, since it uses less digits than its factorization.

21083251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3581.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21083251 is about 4591.6501391112. The cubic root of 21083251 is about 276.2565134313.

Subtracting from 21083251 its product of nonzero digits (480), we obtain a triangular number (21082771 = T₆₄₉₃).

The spelling of 21083251 in words is "twenty-one million, eighty-three thousand, two hundred fifty-one".