21540155033 has 8 divisors (see below), whose sum is σ = 21889410408. Its totient is φ = 21193682944.

The previous prime is 21540155023. The next prime is 21540155047. The reversal of 21540155033 is 33055104512.

It can be written as a sum of positive squares in 4 ways, for example, as 146119744 + 21394035289 = 12088^2 + 146267^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21540155033 - 2⁶ = 21540154969 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21540154987 and 21540155005.

It is not an unprimeable number, because it can be changed into a prime (21540155003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 680216 + ... + 711177.

It is an arithmetic number, because the mean of its divisors is an integer number (2736176301).

Almost surely, 2^21540155033 is an apocalyptic number.

It is an amenable number.

21540155033 is a deficient number, since it is larger than the sum of its proper divisors (349255375).

21540155033 is a wasteful number, since it uses less digits than its factorization.

21540155033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1391643.

The product of its (nonzero) digits is 9000, while the sum is 29.

Adding to 21540155033 its reverse (33055104512), we get a palindrome (54595259545).

The spelling of 21540155033 in words is "twenty-one billion, five hundred forty million, one hundred fifty-five thousand, thirty-three".