21541402509 has 16 divisors (see below), whose sum is σ = 31348062720. Its totient is φ = 13049098160.

The previous prime is 21541402469. The next prime is 21541402529. The reversal of 21541402509 is 90520414512.

It is a cyclic number.

It is not a de Polignac number, because 21541402509 - 2⁹ = 21541401997 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a self number, because there is not a number n which added to its sum of digits gives 21541402509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541402529) 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, 87519 + ... + 225260.

It is an arithmetic number, because the mean of its divisors is an integer number (1959253920).

Almost surely, 2^21541402509 is an apocalyptic number.

It is an amenable number.

21541402509 is a deficient number, since it is larger than the sum of its proper divisors (9806660211).

21541402509 is a wasteful number, since it uses less digits than its factorization.

21541402509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314880.

The product of its (nonzero) digits is 14400, while the sum is 33.

The spelling of 21541402509 in words is "twenty-one billion, five hundred forty-one million, four hundred two thousand, five hundred nine".