21540313153 has 2 divisors, whose sum is σ = 21540313154. Its totient is φ = 21540313152.

The previous prime is 21540313133. The next prime is 21540313163. The reversal of 21540313153 is 35131304512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21459906064 + 80407089 = 146492^2 + 8967^2 .

It is a cyclic number.

It is not a de Polignac number, because 21540313153 - 2⁵ = 21540313121 is a prime.

It is not a weakly prime, because it can be changed into another prime (21540313103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770156576 + 10770156577.

It is an arithmetic number, because the mean of its divisors is an integer number (10770156577).

Almost surely, 2^21540313153 is an apocalyptic number.

It is an amenable number.

21540313153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21540313153 is an equidigital number, since it uses as much as digits as its factorization.

21540313153 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 28.

Adding to 21540313153 its reverse (35131304512), we get a palindrome (56671617665).

The spelling of 21540313153 in words is "twenty-one billion, five hundred forty million, three hundred thirteen thousand, one hundred fifty-three".