21000727 has 16 divisors (see below), whose sum is σ = 24266880. Its totient is φ = 17992800.

The previous prime is 21000709. The next prime is 21000731. The reversal of 21000727 is 72700012.

It is a cyclic number.

It is not a de Polignac number, because 21000727 - 2⁷ = 21000599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12952 + ... + 14482.

It is an arithmetic number, because the mean of its divisors is an integer number (1516680).

Almost surely, 2^21000727 is an apocalyptic number.

21000727 is a deficient number, since it is larger than the sum of its proper divisors (3266153).

21000727 is a wasteful number, since it uses less digits than its factorization.

21000727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1614.

The product of its (nonzero) digits is 196, while the sum is 19.

The square root of 21000727 is about 4582.6550164724. The cubic root of 21000727 is about 275.8956013123.

Adding to 21000727 its reverse (72700012), we get a palindrome (93700739).

The spelling of 21000727 in words is "twenty-one million, seven hundred twenty-seven", and thus it is an aban number.