21506696 has 8 divisors (see below), whose sum is σ = 40325070. Its totient is φ = 10753344.

The previous prime is 21506669. The next prime is 21506707. The reversal of 21506696 is 69660512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16728100 + 4778596 = 4090^2 + 2186^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1344161 + ... + 1344176.

Almost surely, 2^21506696 is an apocalyptic number.

It is an amenable number.

21506696 is a deficient number, since it is larger than the sum of its proper divisors (18818374).

21506696 is a wasteful number, since it uses less digits than its factorization.

21506696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2688343 (or 2688339 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 21506696 is about 4637.5312397870. The cubic root of 21506696 is about 278.0937523452.

The spelling of 21506696 in words is "twenty-one million, five hundred six thousand, six hundred ninety-six".