21760013 has 8 divisors (see below), whose sum is σ = 24243840. Its totient is φ = 19360480.

The previous prime is 21760003. The next prime is 21760019. The reversal of 21760013 is 31006712.

It is a happy number.

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 21760013 - 2⁸ = 21759757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21760019) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20528 + ... + 21561.

It is an arithmetic number, because the mean of its divisors is an integer number (3030480).

Almost surely, 2^21760013 is an apocalyptic number.

It is an amenable number.

21760013 is a deficient number, since it is larger than the sum of its proper divisors (2483827).

21760013 is a wasteful number, since it uses less digits than its factorization.

21760013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42147.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 21760013 is about 4664.7629093020. The cubic root of 21760013 is about 279.1813374731.

Adding to 21760013 its reverse (31006712), we get a palindrome (52766725).

The spelling of 21760013 in words is "twenty-one million, seven hundred sixty thousand, thirteen".