21011342505 has 16 divisors (see below), whose sum is σ = 33669023424. Its totient is φ = 11189090880.

The previous prime is 21011342503. The next prime is 21011342543. The reversal of 21011342505 is 50524311012.

It is a happy number.

It is not a de Polignac number, because 21011342505 - 2¹ = 21011342503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21011342503) 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, 1049659 + ... + 1069488.

It is an arithmetic number, because the mean of its divisors is an integer number (2104313964).

Almost surely, 2^21011342505 is an apocalyptic number.

It is an amenable number.

21011342505 is a deficient number, since it is larger than the sum of its proper divisors (12657680919).

21011342505 is a wasteful number, since it uses less digits than its factorization.

21011342505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2119816.

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21011342505 its reverse (50524311012), we get a palindrome (71535653517).

The spelling of 21011342505 in words is "twenty-one billion, eleven million, three hundred forty-two thousand, five hundred five".