21137706 has 32 divisors (see below), whose sum is σ = 47234880. Its totient is φ = 7006608.

The previous prime is 21137689. The next prime is 21137707. The reversal of 21137706 is 60773112.

It is a super-3 number, since 3×21137706³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21137706.

It is not an unprimeable number, because it can be changed into a prime (21137707) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9645 + ... + 11631.

It is an arithmetic number, because the mean of its divisors is an integer number (1476090).

Almost surely, 2^21137706 is an apocalyptic number.

21137706 is an abundant number, since it is smaller than the sum of its proper divisors (26097174).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21137706 is a wasteful number, since it uses less digits than its factorization.

21137706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2195 (or 2189 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 21137706 is about 4597.5761005121. The cubic root of 21137706 is about 276.4941525446.

The spelling of 21137706 in words is "twenty-one million, one hundred thirty-seven thousand, seven hundred six".