21961825459 has 16 divisors (see below), whose sum is σ = 25191421632. Its totient is φ = 18755371008.

The previous prime is 21961825453. The next prime is 21961825463. The reversal of 21961825459 is 95452816912.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21961825459 - 2¹⁷ = 21961694387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21961825453) 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, 3686227 + ... + 3692179.

It is an arithmetic number, because the mean of its divisors is an integer number (1574463852).

Almost surely, 2^21961825459 is an apocalyptic number.

21961825459 is a deficient number, since it is larger than the sum of its proper divisors (3229596173).

21961825459 is a wasteful number, since it uses less digits than its factorization.

21961825459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7806.

The product of its digits is 1555200, while the sum is 52.

The spelling of 21961825459 in words is "twenty-one billion, nine hundred sixty-one million, eight hundred twenty-five thousand, four hundred fifty-nine".