21370686 has 16 divisors (see below), whose sum is σ = 42810768. Its totient is φ = 7112000.

The previous prime is 21370681. The next prime is 21370693. The reversal of 21370686 is 68607312.

It is a super-2 number, since 2×21370686² = 913412440221192, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21370681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1666 + ... + 6746.

It is an arithmetic number, because the mean of its divisors is an integer number (2675673).

Almost surely, 2^21370686 is an apocalyptic number.

21370686 is an abundant number, since it is smaller than the sum of its proper divisors (21440082).

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

21370686 is a wasteful number, since it uses less digits than its factorization.

21370686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5787.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21370686 is about 4622.8439298769. The cubic root of 21370686 is about 277.5062834386.

Adding to 21370686 its reverse (68607312), we get a palindrome (89977998).

The spelling of 21370686 in words is "twenty-one million, three hundred seventy thousand, six hundred eighty-six".