21242450509 has 64 divisors (see below), whose sum is σ = 27544043520. Its totient is φ = 15971904000.

The previous prime is 21242450501. The next prime is 21242450549. The reversal of 21242450509 is 90505424212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21242450509 - 2³ = 21242450501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242450501) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8958094 + ... + 8960464.

It is an arithmetic number, because the mean of its divisors is an integer number (430375680).

Almost surely, 2^21242450509 is an apocalyptic number.

It is an amenable number.

21242450509 is a deficient number, since it is larger than the sum of its proper divisors (6301593011).

21242450509 is a wasteful number, since it uses less digits than its factorization.

21242450509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2522.

The product of its (nonzero) digits is 28800, while the sum is 34.

The spelling of 21242450509 in words is "twenty-one billion, two hundred forty-two million, four hundred fifty thousand, five hundred nine".