21405126017 has 8 divisors (see below), whose sum is σ = 23353762752. Its totient is φ = 19456942000.

The previous prime is 21405126013. The next prime is 21405126121. The reversal of 21405126017 is 71062150412.

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

It is a cyclic number.

It is not a de Polignac number, because 21405126017 - 2² = 21405126013 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21405126013) 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, 10238 + ... + 207159.

It is an arithmetic number, because the mean of its divisors is an integer number (2919220344).

Almost surely, 2^21405126017 is an apocalyptic number.

It is an amenable number.

21405126017 is a deficient number, since it is larger than the sum of its proper divisors (1948636735).

21405126017 is a wasteful number, since it uses less digits than its factorization.

21405126017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226359.

The product of its (nonzero) digits is 3360, while the sum is 29.

Adding to 21405126017 its reverse (71062150412), we get a palindrome (92467276429).

The spelling of 21405126017 in words is "twenty-one billion, four hundred five million, one hundred twenty-six thousand, seventeen".