21456131355 has 12 divisors (see below), whose sum is σ = 37190627760. Its totient is φ = 11443270032.

The previous prime is 21456131353. The next prime is 21456131383. The reversal of 21456131355 is 55313165412.

21456131355 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 613 + 1 + 35 + 5 = 666.

It is not a de Polignac number, because 21456131355 - 2¹ = 21456131353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21456131353) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 238401415 + ... + 238401504.

It is an arithmetic number, because the mean of its divisors is an integer number (3099218980).

Almost surely, 2^21456131355 is an apocalyptic number.

21456131355 is a deficient number, since it is larger than the sum of its proper divisors (15734496405).

21456131355 is a wasteful number, since it uses less digits than its factorization.

21456131355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476802930 (or 476802927 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

Adding to 21456131355 its reverse (55313165412), we get a palindrome (76769296767).

The spelling of 21456131355 in words is "twenty-one billion, four hundred fifty-six million, one hundred thirty-one thousand, three hundred fifty-five".