21755327 has 4 divisors (see below), whose sum is σ = 23733096. Its totient is φ = 19777560.

The previous prime is 21755267. The next prime is 21755329. The reversal of 21755327 is 72355712.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-21755327 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21755293 and 21755302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21755329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 988868 + ... + 988889.

It is an arithmetic number, because the mean of its divisors is an integer number (5933274).

Almost surely, 2^21755327 is an apocalyptic number.

21755327 is a deficient number, since it is larger than the sum of its proper divisors (1977769).

21755327 is a wasteful number, since it uses less digits than its factorization.

21755327 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1977768.

The product of its digits is 14700, while the sum is 32.

The square root of 21755327 is about 4664.2606059267. The cubic root of 21755327 is about 279.1612955478.

The spelling of 21755327 in words is "twenty-one million, seven hundred fifty-five thousand, three hundred twenty-seven".