21319505 has 16 divisors (see below), whose sum is σ = 27008640. Its totient is φ = 16123008.

The previous prime is 21319499. The next prime is 21319523. The reversal of 21319505 is 50591312.

It is a cyclic number.

It is not a de Polignac number, because 21319505 - 2⁴ = 21319489 is a prime.

It is a plaindrome in base 13.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9194 + ... + 11276.

It is an arithmetic number, because the mean of its divisors is an integer number (1688040).

Almost surely, 2^21319505 is an apocalyptic number.

It is an amenable number.

21319505 is a deficient number, since it is larger than the sum of its proper divisors (5689135).

21319505 is a wasteful number, since it uses less digits than its factorization.

21319505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 21319505 is about 4617.3049498598. The cubic root of 21319505 is about 277.2845715951.

The spelling of 21319505 in words is "twenty-one million, three hundred nineteen thousand, five hundred five".