21354321240451 has 4 divisors (see below), whose sum is σ = 21356337902400. Its totient is φ = 21352304578504.

The previous prime is 21354321240397. The next prime is 21354321240493. The reversal of 21354321240451 is 15404212345312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21354321240451 - 2²¹ = 21354319143299 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21354321240451.

It is not an unprimeable number, because it can be changed into a prime (21354321247451) 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, 1008315091 + ... + 1008336268.

It is an arithmetic number, because the mean of its divisors is an integer number (5339084475600).

Almost surely, 2^{21354321240451} is an apocalyptic number.

21354321240451 is a deficient number, since it is larger than the sum of its proper divisors (2016661949).

21354321240451 is a wasteful number, since it uses less digits than its factorization.

21354321240451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2016661948.

The product of its (nonzero) digits is 115200, while the sum is 37.

Adding to 21354321240451 its reverse (15404212345312), we get a palindrome (36758533585763).

The spelling of 21354321240451 in words is "twenty-one trillion, three hundred fifty-four billion, three hundred twenty-one million, two hundred forty thousand, four hundred fifty-one".