21042696907 has 4 divisors (see below), whose sum is σ = 21044519896. Its totient is φ = 21040873920.

The previous prime is 21042696893. The next prime is 21042696919. The reversal of 21042696907 is 70969624012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042696907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21042696947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 894069 + ... + 917302.

It is an arithmetic number, because the mean of its divisors is an integer number (5261129974).

Almost surely, 2^21042696907 is an apocalyptic number.

21042696907 is a deficient number, since it is larger than the sum of its proper divisors (1822989).

21042696907 is a wasteful number, since it uses less digits than its factorization.

21042696907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1822988.

The product of its (nonzero) digits is 326592, while the sum is 46.

The spelling of 21042696907 in words is "twenty-one billion, forty-two million, six hundred ninety-six thousand, nine hundred seven".