21460509 has 12 divisors (see below), whose sum is σ = 35426976. Its totient is φ = 12263112.

The previous prime is 21460501. The next prime is 21460547. The reversal of 21460509 is 90506412.

It is not a de Polignac number, because 21460509 - 2³ = 21460501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21460501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 170259 + ... + 170384.

It is an arithmetic number, because the mean of its divisors is an integer number (2952248).

Almost surely, 2^21460509 is an apocalyptic number.

It is an amenable number.

21460509 is a deficient number, since it is larger than the sum of its proper divisors (13966467).

21460509 is a wasteful number, since it uses less digits than its factorization.

21460509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340656 (or 340653 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21460509 is about 4632.5488664449. The cubic root of 21460509 is about 277.8945349822.

The spelling of 21460509 in words is "twenty-one million, four hundred sixty thousand, five hundred nine".