21545331105355 has 4 divisors (see below), whose sum is σ = 25854397326432. Its totient is φ = 17236264884280.

The previous prime is 21545331105329. The next prime is 21545331105359. The reversal of 21545331105355 is 55350113354512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21545331105355 - 2¹⁹ = 21545330581067 is a prime.

It is a super-2 number, since 2×21545331105355² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21545331105359) 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, 2154533110531 + ... + 2154533110540.

It is an arithmetic number, because the mean of its divisors is an integer number (6463599331608).

Almost surely, 2^{21545331105355} is an apocalyptic number.

21545331105355 is a deficient number, since it is larger than the sum of its proper divisors (4309066221077).

21545331105355 is an equidigital number, since it uses as much as digits as its factorization.

21545331105355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4309066221076.

The product of its (nonzero) digits is 675000, while the sum is 43.

Adding to 21545331105355 its reverse (55350113354512), we get a palindrome (76895444459867).

The spelling of 21545331105355 in words is "twenty-one trillion, five hundred forty-five billion, three hundred thirty-one million, one hundred five thousand, three hundred fifty-five".