21701513 has 8 divisors (see below), whose sum is σ = 22085448. Its totient is φ = 21320064.

The previous prime is 21701497. The next prime is 21701531. The reversal of 21701513 is 31510712.

It can be written as a sum of positive squares in 4 ways, for example, as 3952144 + 17749369 = 1988^2 + 4213^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21701513 - 2⁴ = 21701497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21701413) 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 7 ways as a sum of consecutive naturals, for example, 26831 + ... + 27627.

It is an arithmetic number, because the mean of its divisors is an integer number (2760681).

Almost surely, 2^21701513 is an apocalyptic number.

It is an amenable number.

21701513 is a deficient number, since it is larger than the sum of its proper divisors (383935).

21701513 is an equidigital number, since it uses as much as digits as its factorization.

21701513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21701513 is about 4658.4882741078. The cubic root of 21701513 is about 278.9309276046.

The spelling of 21701513 in words is "twenty-one million, seven hundred one thousand, five hundred thirteen".