21906701 has 4 divisors (see below), whose sum is σ = 22498812. Its totient is φ = 21314592.

The previous prime is 21906697. The next prime is 21906707. The reversal of 21906701 is 10760912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18913801 + 2992900 = 4349^2 + 1730^2 .

It is a cyclic number.

It is not a de Polignac number, because 21906701 - 2² = 21906697 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21906707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 296000 + ... + 296073.

It is an arithmetic number, because the mean of its divisors is an integer number (5624703).

Almost surely, 2^21906701 is an apocalyptic number.

It is an amenable number.

21906701 is a deficient number, since it is larger than the sum of its proper divisors (592111).

21906701 is an equidigital number, since it uses as much as digits as its factorization.

21906701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592110.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 21906701 is about 4680.4594859907. The cubic root of 21906701 is about 279.8072695806.

The spelling of 21906701 in words is "twenty-one million, nine hundred six thousand, seven hundred one".