21197755 has 8 divisors (see below), whose sum is σ = 25462224. Its totient is φ = 16941600.

The previous prime is 21197731. The next prime is 21197767. The reversal of 21197755 is 55779112.

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

It is a de Polignac number, because none of the positive numbers 2^k-21197755 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7885 + ... + 10225.

It is an arithmetic number, because the mean of its divisors is an integer number (3182778).

Almost surely, 2^21197755 is an apocalyptic number.

21197755 is a deficient number, since it is larger than the sum of its proper divisors (4264469).

21197755 is a wasteful number, since it uses less digits than its factorization.

21197755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4157.

The product of its digits is 22050, while the sum is 37.

The square root of 21197755 is about 4604.1019754128. The cubic root of 21197755 is about 276.7557309100.

It can be divided in two parts, 21197 and 755, that added together give a cube (21952 = 28³).

The spelling of 21197755 in words is "twenty-one million, one hundred ninety-seven thousand, seven hundred fifty-five".