21311712 has 36 divisors (see below), whose sum is σ = 60606000. Its totient is φ = 7103808.

The previous prime is 21311701. The next prime is 21311729. The reversal of 21311712 is 21711312.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

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, 36712 + ... + 37287.

It is an arithmetic number, because the mean of its divisors is an integer number (1683500).

Almost surely, 2^21311712 is an apocalyptic number.

It is an amenable number.

21311712 is an abundant number, since it is smaller than the sum of its proper divisors (39294288).

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

21311712 is a wasteful number, since it uses less digits than its factorization.

21311712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74015 (or 74004 counting only the distinct ones).

The product of its digits is 84, while the sum is 18.

The square root of 21311712 is about 4616.4609821810. The cubic root of 21311712 is about 277.2507818485.

The spelling of 21311712 in words is "twenty-one million, three hundred eleven thousand, seven hundred twelve".