21041340251 has 8 divisors (see below), whose sum is σ = 21174308304. Its totient is φ = 20908419840.

The previous prime is 21041340233. The next prime is 21041340323. The reversal of 21041340251 is 15204314012.

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 21041340251 - 2²⁶ = 20974231387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21041340211) 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, 1383971 + ... + 1399091.

It is an arithmetic number, because the mean of its divisors is an integer number (2646788538).

Almost surely, 2^21041340251 is an apocalyptic number.

21041340251 is a deficient number, since it is larger than the sum of its proper divisors (132968053).

21041340251 is a wasteful number, since it uses less digits than its factorization.

21041340251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23821.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21041340251 its reverse (15204314012), we get a palindrome (36245654263).

The spelling of 21041340251 in words is "twenty-one billion, forty-one million, three hundred forty thousand, two hundred fifty-one".