21145340454 has 64 divisors (see below), whose sum is σ = 49585181184. Its totient is φ = 5886902016.

The previous prime is 21145340449. The next prime is 21145340473. The reversal of 21145340454 is 45404354112.

It is a happy number.

It is a super-2 number, since 2×21145340454² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 212932 + ... + 296024.

It is an arithmetic number, because the mean of its divisors is an integer number (774768456).

Almost surely, 2^21145340454 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21145340454, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24792590592).

21145340454 is an abundant number, since it is smaller than the sum of its proper divisors (28439840730).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21145340454 is a wasteful number, since it uses less digits than its factorization.

21145340454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83261.

The product of its (nonzero) digits is 38400, while the sum is 33.

Adding to 21145340454 its reverse (45404354112), we get a palindrome (66549694566).

The spelling of 21145340454 in words is "twenty-one billion, one hundred forty-five million, three hundred forty thousand, four hundred fifty-four".