20686716 has 18 divisors (see below), whose sum is σ = 52291512. Its totient is φ = 6895560.

The previous prime is 20686709. The next prime is 20686723. The reversal of 20686716 is 61768602.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20686709) and next prime (20686723).

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-3 number, since 3×20686716³ (a number of 23 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 574631 = 20686716 / (2 + 0 + 6 + 8 + 6 + 7 + 1 + 6).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 287280 + ... + 287351.

It is an arithmetic number, because the mean of its divisors is an integer number (2905084).

Almost surely, 2^20686716 is an apocalyptic number.

It is an amenable number.

20686716 is an abundant number, since it is smaller than the sum of its proper divisors (31604796).

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

20686716 is a wasteful number, since it uses less digits than its factorization.

20686716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574641 (or 574636 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 20686716 is about 4548.2651637740. The cubic root of 20686716 is about 274.5135908547.

The spelling of 20686716 in words is "twenty million, six hundred eighty-six thousand, seven hundred sixteen".