21540344552 has 8 divisors (see below), whose sum is σ = 40388146050. Its totient is φ = 10770172272.

The previous prime is 21540344521. The next prime is 21540344557. The reversal of 21540344552 is 25544304512.

It can be written as a sum of positive squares in only one way, i.e., 20012629156 + 1527715396 = 141466^2 + 39086^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21540344557) 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 as a sum of consecutive naturals, namely, 1346271527 + ... + 1346271542.

Almost surely, 2^21540344552 is an apocalyptic number.

It is an amenable number.

21540344552 is a deficient number, since it is larger than the sum of its proper divisors (18847801498).

21540344552 is a wasteful number, since it uses less digits than its factorization.

21540344552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2692543075 (or 2692543071 counting only the distinct ones).

The product of its (nonzero) digits is 96000, while the sum is 35.

The spelling of 21540344552 in words is "twenty-one billion, five hundred forty million, three hundred forty-four thousand, five hundred fifty-two".