21240034405 has 16 divisors (see below), whose sum is σ = 25898906880. Its totient is φ = 16719588288.

The previous prime is 21240034367. The next prime is 21240034423. The reversal of 21240034405 is 50443004212.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21240034405 is a prime.

It is a super-2 number, since 2×21240034405² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21240034405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23974 + ... + 207496.

It is an arithmetic number, because the mean of its divisors is an integer number (1618681680).

Almost surely, 2^21240034405 is an apocalyptic number.

It is an amenable number.

21240034405 is a deficient number, since it is larger than the sum of its proper divisors (4658872475).

21240034405 is a wasteful number, since it uses less digits than its factorization.

21240034405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183900.

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21240034405 its reverse (50443004212), we get a palindrome (71683038617).

The spelling of 21240034405 in words is "twenty-one billion, two hundred forty million, thirty-four thousand, four hundred five".