21400354109 has 4 divisors (see below), whose sum is σ = 21400706880. Its totient is φ = 21400001340.

The previous prime is 21400354099. The next prime is 21400354123. The reversal of 21400354109 is 90145300412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21400354109 - 2²⁸ = 21131918653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400354009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59627 + ... + 215304.

It is an arithmetic number, because the mean of its divisors is an integer number (5350176720).

Almost surely, 2^21400354109 is an apocalyptic number.

It is an amenable number.

21400354109 is a deficient number, since it is larger than the sum of its proper divisors (352771).

21400354109 is an equidigital number, since it uses as much as digits as its factorization.

21400354109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352770.

The product of its (nonzero) digits is 4320, while the sum is 29.

The spelling of 21400354109 in words is "twenty-one billion, four hundred million, three hundred fifty-four thousand, one hundred nine".