21236154257 has 8 divisors (see below), whose sum is σ = 21359289600. Its totient is φ = 21113183520.

The previous prime is 21236154179. The next prime is 21236154259. The reversal of 21236154257 is 75245163212.

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

It is a cyclic number.

It is not a de Polignac number, because 21236154257 - 2⁸ = 21236154001 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21236154257.

It is not an unprimeable number, because it can be changed into a prime (21236154259) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 222488 + ... + 303270.

It is an arithmetic number, because the mean of its divisors is an integer number (2669911200).

Almost surely, 2^21236154257 is an apocalyptic number.

It is an amenable number.

21236154257 is a deficient number, since it is larger than the sum of its proper divisors (123135343).

21236154257 is a wasteful number, since it uses less digits than its factorization.

21236154257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82303.

The product of its digits is 100800, while the sum is 38.

The spelling of 21236154257 in words is "twenty-one billion, two hundred thirty-six million, one hundred fifty-four thousand, two hundred fifty-seven".