21275789 has 8 divisors (see below), whose sum is σ = 22845888. Its totient is φ = 19741120.

The previous prime is 21275747. The next prime is 21275809. The reversal of 21275789 is 98757212.

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

It is a cyclic number.

It is not a de Polignac number, because 21275789 - 2⁸ = 21275533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275489) 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, 7607 + ... + 10020.

It is an arithmetic number, because the mean of its divisors is an integer number (2855736).

Almost surely, 2^21275789 is an apocalyptic number.

It is an amenable number.

21275789 is a deficient number, since it is larger than the sum of its proper divisors (1570099).

21275789 is a wasteful number, since it uses less digits than its factorization.

21275789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17715.

The product of its digits is 70560, while the sum is 41.

The square root of 21275789 is about 4612.5685902759. The cubic root of 21275789 is about 277.0949163618.

It can be divided in two parts, 2127 and 5789, that multiplied together give a triangular number (12313203 = T₄₉₆₂).

The spelling of 21275789 in words is "twenty-one million, two hundred seventy-five thousand, seven hundred eighty-nine".