21423342561 has 8 divisors (see below), whose sum is σ = 28571247264. Its totient is φ = 14278833120.

The previous prime is 21423342541. The next prime is 21423342569. The reversal of 21423342561 is 16524332412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21423342561 - 2⁹ = 21423342049 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21423342569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 834055 + ... + 859356.

It is an arithmetic number, because the mean of its divisors is an integer number (3571405908).

Almost surely, 2^21423342561 is an apocalyptic number.

It is an amenable number.

21423342561 is a deficient number, since it is larger than the sum of its proper divisors (7147904703).

21423342561 is a wasteful number, since it uses less digits than its factorization.

21423342561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1697631.

The product of its digits is 34560, while the sum is 33.

Adding to 21423342561 its reverse (16524332412), we get a palindrome (37947674973).

The spelling of 21423342561 in words is "twenty-one billion, four hundred twenty-three million, three hundred forty-two thousand, five hundred sixty-one".