21013715 has 8 divisors (see below), whose sum is σ = 26543760. Its totient is φ = 15926112.

The previous prime is 21013711. The next prime is 21013723. The reversal of 21013715 is 51731012.

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 21013715 - 2² = 21013711 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21013711) 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, 110504 + ... + 110693.

It is an arithmetic number, because the mean of its divisors is an integer number (3317970).

Almost surely, 2^21013715 is an apocalyptic number.

21013715 is a deficient number, since it is larger than the sum of its proper divisors (5530045).

21013715 is a wasteful number, since it uses less digits than its factorization.

21013715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221221.

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

The square root of 21013715 is about 4584.0718798902. The cubic root of 21013715 is about 275.9524659090.

Adding to 21013715 its reverse (51731012), we get a palindrome (72744727).

The spelling of 21013715 in words is "twenty-one million, thirteen thousand, seven hundred fifteen".