21429609291 has 24 divisors (see below), whose sum is σ = 31820951760. Its totient is φ = 14253458688.

The previous prime is 21429609281. The next prime is 21429609307. The reversal of 21429609291 is 19290692412.

21429609291 is a `hidden beast` number, since 2 + 14 + 2 + 9 + 609 + 29 + 1 = 666.

It is not a de Polignac number, because 21429609291 - 2⁵ = 21429609259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21429609221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6829675 + ... + 6832811.

It is an arithmetic number, because the mean of its divisors is an integer number (1325872990).

Almost surely, 2^21429609291 is an apocalyptic number.

21429609291 is a deficient number, since it is larger than the sum of its proper divisors (10391342469).

21429609291 is an frugal number, since it uses more digits than its factorization.

21429609291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4152 (or 3643 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The spelling of 21429609291 in words is "twenty-one billion, four hundred twenty-nine million, six hundred nine thousand, two hundred ninety-one".