21142060561 has 4 divisors (see below), whose sum is σ = 21633736432. Its totient is φ = 20650384692.

The previous prime is 21142060519. The next prime is 21142060573. The reversal of 21142060561 is 16506024112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21142060561 - 2¹¹ = 21142058513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21142061561) 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, 245837871 + ... + 245837956.

It is an arithmetic number, because the mean of its divisors is an integer number (5408434108).

Almost surely, 2^21142060561 is an apocalyptic number.

It is an amenable number.

21142060561 is a deficient number, since it is larger than the sum of its proper divisors (491675871).

21142060561 is an equidigital number, since it uses as much as digits as its factorization.

21142060561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491675870.

The product of its (nonzero) digits is 2880, while the sum is 28.

Adding to 21142060561 its reverse (16506024112), we get a palindrome (37648084673).

The spelling of 21142060561 in words is "twenty-one billion, one hundred forty-two million, sixty thousand, five hundred sixty-one".