21407789291 has 24 divisors (see below), whose sum is σ = 26404068960. Its totient is φ = 17246406912.

The previous prime is 21407789267. The next prime is 21407789297. The reversal of 21407789291 is 19298770412.

It is not a de Polignac number, because 21407789291 - 2¹⁰ = 21407788267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21407789297) 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 23 ways as a sum of consecutive naturals, for example, 601625 + ... + 636213.

It is an arithmetic number, because the mean of its divisors is an integer number (1100169540).

Almost surely, 2^21407789291 is an apocalyptic number.

21407789291 is a deficient number, since it is larger than the sum of its proper divisors (4996279669).

21407789291 is a wasteful number, since it uses less digits than its factorization.

21407789291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35363 (or 35356 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 50.

The spelling of 21407789291 in words is "twenty-one billion, four hundred seven million, seven hundred eighty-nine thousand, two hundred ninety-one".