21065706 has 12 divisors (see below), whose sum is σ = 45642402. Its totient is φ = 7021896.

The previous prime is 21065701. The next prime is 21065711. The reversal of 21065706 is 60756012.

21065706 is a `hidden beast` number, since 2 + 1 + 0 + 657 + 0 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (21065701) and next prime (21065711).

It can be written as a sum of positive squares in only one way, i.e., 13727025 + 7338681 = 3705^2 + 2709^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21065706.

It is not an unprimeable number, because it can be changed into a prime (21065701) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 585141 + ... + 585176.

Almost surely, 2^21065706 is an apocalyptic number.

21065706 is an abundant number, since it is smaller than the sum of its proper divisors (24576696).

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

21065706 is a wasteful number, since it uses less digits than its factorization.

21065706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1170325 (or 1170322 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 21065706 is about 4589.7392082775. The cubic root of 21065706 is about 276.1798607107.

The spelling of 21065706 in words is "twenty-one million, sixty-five thousand, seven hundred six".