21545121321530 has 8 divisors (see below), whose sum is σ = 38781218378772. Its totient is φ = 8618048528608.

The previous prime is 21545121321517. The next prime is 21545121321539. The reversal of 21545121321530 is 3512312154512.

It can be written as a sum of positive squares in 2 ways, for example, as 19398113940241 + 2147007381289 = 4404329^2 + 1465267^2 .

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

It is a super-2 number, since 2×21545121321530² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21545121321539) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1077256066067 + ... + 1077256066086.

Almost surely, 2^{21545121321530} is an apocalyptic number.

21545121321530 is a deficient number, since it is larger than the sum of its proper divisors (17236097057242).

21545121321530 is a wasteful number, since it uses less digits than its factorization.

21545121321530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2154512132160.

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 21545121321530 in words is "twenty-one trillion, five hundred forty-five billion, one hundred twenty-one million, three hundred twenty-one thousand, five hundred thirty".