21435138769 has 4 divisors (see below), whose sum is σ = 23383787760. Its totient is φ = 19486489780.

The previous prime is 21435138749. The next prime is 21435138833. The reversal of 21435138769 is 96783153412.

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 21435138769 - 2¹⁵ = 21435106001 is a prime.

It is a super-2 number, since 2×21435138769² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21435138749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 974324479 + ... + 974324500.

It is an arithmetic number, because the mean of its divisors is an integer number (5845946940).

Almost surely, 2^21435138769 is an apocalyptic number.

It is an amenable number.

21435138769 is a deficient number, since it is larger than the sum of its proper divisors (1948648991).

21435138769 is a wasteful number, since it uses less digits than its factorization.

21435138769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1948648990.

The product of its digits is 1088640, while the sum is 49.

The spelling of 21435138769 in words is "twenty-one billion, four hundred thirty-five million, one hundred thirty-eight thousand, seven hundred sixty-nine".