21540455345 has 16 divisors (see below), whose sum is σ = 26233320960. Its totient is φ = 16976232000.

The previous prime is 21540455341. The next prime is 21540455347. The reversal of 21540455345 is 54355404512.

It is not a de Polignac number, because 21540455345 - 2² = 21540455341 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21540455299 and 21540455308.

It is not an unprimeable number, because it can be changed into a prime (21540455341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 438536 + ... + 485174.

It is an arithmetic number, because the mean of its divisors is an integer number (1639582560).

Almost surely, 2^21540455345 is an apocalyptic number.

It is an amenable number.

21540455345 is a deficient number, since it is larger than the sum of its proper divisors (4692865615).

21540455345 is a wasteful number, since it uses less digits than its factorization.

21540455345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48016.

The product of its (nonzero) digits is 240000, while the sum is 38.

Adding to 21540455345 its reverse (54355404512), we get a palindrome (75895859857).

The spelling of 21540455345 in words is "twenty-one billion, five hundred forty million, four hundred fifty-five thousand, three hundred forty-five".