21012759 has 6 divisors (see below), whose sum is σ = 30351776. Its totient is φ = 14008500.

The previous prime is 21012749. The next prime is 21012773. The reversal of 21012759 is 95721012.

It is not a de Polignac number, because 21012759 - 2⁴ = 21012743 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 (21012749) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1167367 + ... + 1167384.

Almost surely, 2^21012759 is an apocalyptic number.

21012759 is a deficient number, since it is larger than the sum of its proper divisors (9339017).

21012759 is a wasteful number, since it uses less digits than its factorization.

21012759 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2334757 (or 2334754 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21012759 is about 4583.9676045976. The cubic root of 21012759 is about 275.9482811094.

The spelling of 21012759 in words is "twenty-one million, twelve thousand, seven hundred fifty-nine".