21431403565 has 128 divisors (see below), whose sum is σ = 32690552832. Its totient is φ = 13264542720.

The previous prime is 21431403559. The next prime is 21431403589. The reversal of 21431403565 is 56530413412.

It is not a de Polignac number, because 21431403565 - 2³ = 21431403557 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21431403565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 58396012 + ... + 58396378.

It is an arithmetic number, because the mean of its divisors is an integer number (255394944).

Almost surely, 2^21431403565 is an apocalyptic number.

It is an amenable number.

21431403565 is a deficient number, since it is larger than the sum of its proper divisors (11259149267).

21431403565 is a wasteful number, since it uses less digits than its factorization.

21431403565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539.

The product of its (nonzero) digits is 43200, while the sum is 34.

Adding to 21431403565 its reverse (56530413412), we get a palindrome (77961816977).

The spelling of 21431403565 in words is "twenty-one billion, four hundred thirty-one million, four hundred three thousand, five hundred sixty-five".