21340120021 has 8 divisors (see below), whose sum is σ = 23282648064. Its totient is φ = 19398011520.

The previous prime is 21340120019. The next prime is 21340120027. The reversal of 21340120021 is 12002104312.

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 21340120021 - 2¹ = 21340120019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21340119977 and 21340120004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340120027) 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, 6636 + ... + 206698.

It is an arithmetic number, because the mean of its divisors is an integer number (2910331008).

Almost surely, 2^21340120021 is an apocalyptic number.

It is an amenable number.

21340120021 is a deficient number, since it is larger than the sum of its proper divisors (1942528043).

21340120021 is a wasteful number, since it uses less digits than its factorization.

21340120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209771.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21340120021 its reverse (12002104312), we get a palindrome (33342224333).

The spelling of 21340120021 in words is "twenty-one billion, three hundred forty million, one hundred twenty thousand, twenty-one".