26691691631 has 4 divisors (see below), whose sum is σ = 29118209064. Its totient is φ = 24265174200.

The previous prime is 26691691597. The next prime is 26691691643. The reversal of 26691691631 is 13619619662.

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

It is a cyclic number.

It is not a de Polignac number, because 26691691631 - 2¹⁰ = 26691690607 is a prime.

It is a super-2 number, since 2×26691691631² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 26691691631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26691691661) 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, 1213258700 + ... + 1213258721.

It is an arithmetic number, because the mean of its divisors is an integer number (7279552266).

Almost surely, 2^26691691631 is an apocalyptic number.

26691691631 is a deficient number, since it is larger than the sum of its proper divisors (2426517433).

26691691631 is a wasteful number, since it uses less digits than its factorization.

26691691631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2426517432.

The product of its digits is 629856, while the sum is 50.

The spelling of 26691691631 in words is "twenty-six billion, six hundred ninety-one million, six hundred ninety-one thousand, six hundred thirty-one".