21197756 has 12 divisors (see below), whose sum is σ = 37725240. Its totient is φ = 10419120.

The previous prime is 21197731. The next prime is 21197767. The reversal of 21197756 is 65779112.

It is a congruent number.

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, 44675 + ... + 45146.

It is an arithmetic number, because the mean of its divisors is an integer number (3143770).

Almost surely, 2^21197756 is an apocalyptic number.

It is an amenable number.

21197756 is a deficient number, since it is larger than the sum of its proper divisors (16527484).

21197756 is a wasteful number, since it uses less digits than its factorization.

21197756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89884 (or 89882 counting only the distinct ones).

The product of its digits is 26460, while the sum is 38.

The square root of 21197756 is about 4604.1020840116. The cubic root of 21197756 is about 276.7557352619.

The spelling of 21197756 in words is "twenty-one million, one hundred ninety-seven thousand, seven hundred fifty-six".