21755738 has 8 divisors (see below), whose sum is σ = 33686400. Its totient is φ = 10526940.

The previous prime is 21755717. The next prime is 21755761. The reversal of 21755738 is 83755712.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 175388 + ... + 175511.

It is an arithmetic number, because the mean of its divisors is an integer number (4210800).

Almost surely, 2^21755738 is an apocalyptic number.

21755738 is a deficient number, since it is larger than the sum of its proper divisors (11930662).

21755738 is a wasteful number, since it uses less digits than its factorization.

21755738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350932.

The product of its digits is 58800, while the sum is 38.

The square root of 21755738 is about 4664.3046641488. The cubic root of 21755738 is about 279.1630535014.

It can be divided in two parts, 217 and 55738, that added together give a palindrome (55955).

The spelling of 21755738 in words is "twenty-one million, seven hundred fifty-five thousand, seven hundred thirty-eight".