21709491089 has 16 divisors (see below), whose sum is σ = 26384339520. Its totient is φ = 17589552960.

The previous prime is 21709491077. The next prime is 21709491127. The reversal of 21709491089 is 98019490712.

It is a cyclic number.

It is not a de Polignac number, because 21709491089 - 2⁸ = 21709490833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21709491019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2613347 + ... + 2621640.

It is an arithmetic number, because the mean of its divisors is an integer number (1649021220).

Almost surely, 2^21709491089 is an apocalyptic number.

21709491089 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21709491089 is a deficient number, since it is larger than the sum of its proper divisors (4674848431).

21709491089 is a wasteful number, since it uses less digits than its factorization.

21709491089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5235040.

The product of its (nonzero) digits is 326592, while the sum is 50.

The spelling of 21709491089 in words is "twenty-one billion, seven hundred nine million, four hundred ninety-one thousand, eighty-nine".