21530240061 has 16 divisors (see below), whose sum is σ = 31376616960. Its totient is φ = 13023670320.

The previous prime is 21530240033. The next prime is 21530240101. The reversal of 21530240061 is 16004203512.

It is not a de Polignac number, because 21530240061 - 2⁵ = 21530240029 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530240761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 606481 + ... + 640998.

It is an arithmetic number, because the mean of its divisors is an integer number (1961038560).

Almost surely, 2^21530240061 is an apocalyptic number.

It is an amenable number.

21530240061 is a deficient number, since it is larger than the sum of its proper divisors (9846376899).

21530240061 is a wasteful number, since it uses less digits than its factorization.

21530240061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1248016.

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 21530240061 its reverse (16004203512), we get a palindrome (37534443573).

The spelling of 21530240061 in words is "twenty-one billion, five hundred thirty million, two hundred forty thousand, sixty-one".