21008691434 has 8 divisors (see below), whose sum is σ = 31818989280. Its totient is φ = 10402361676.

The previous prime is 21008691377. The next prime is 21008691461. The reversal of 21008691434 is 43419680012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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, 50991764 + ... + 50992175.

It is an arithmetic number, because the mean of its divisors is an integer number (3977373660).

Almost surely, 2^21008691434 is an apocalyptic number.

21008691434 is a deficient number, since it is larger than the sum of its proper divisors (10810297846).

21008691434 is a wasteful number, since it uses less digits than its factorization.

21008691434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101984044.

The product of its (nonzero) digits is 41472, while the sum is 38.

The spelling of 21008691434 in words is "twenty-one billion, eight million, six hundred ninety-one thousand, four hundred thirty-four".