21436025647 has 4 divisors (see below), whose sum is σ = 21436611336. Its totient is φ = 21435439960.

The previous prime is 21436025641. The next prime is 21436025683. The reversal of 21436025647 is 74652063412.

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 21436025647 - 2⁷ = 21436025519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21436025641) 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, 234004 + ... + 312457.

It is an arithmetic number, because the mean of its divisors is an integer number (5359152834).

Almost surely, 2^21436025647 is an apocalyptic number.

21436025647 is a deficient number, since it is larger than the sum of its proper divisors (585689).

21436025647 is an equidigital number, since it uses as much as digits as its factorization.

21436025647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 585688.

The product of its (nonzero) digits is 241920, while the sum is 40.

The spelling of 21436025647 in words is "twenty-one billion, four hundred thirty-six million, twenty-five thousand, six hundred forty-seven".