21041424251 has 8 divisors (see below), whose sum is σ = 21743145984. Its totient is φ = 20341137960.

The previous prime is 21041424247. The next prime is 21041424269. The reversal of 21041424251 is 15242414012.

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 21041424251 - 2² = 21041424247 is a prime.

It is a super-2 number, since 2×21041424251² (a number of 21 digits) contains 22 as substring.

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 21041424251.

It is not an unprimeable number, because it can be changed into a prime (21041424281) 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, 329015 + ... + 387728.

It is an arithmetic number, because the mean of its divisors is an integer number (2717893248).

Almost surely, 2^21041424251 is an apocalyptic number.

21041424251 is a deficient number, since it is larger than the sum of its proper divisors (701721733).

21041424251 is an equidigital number, since it uses as much as digits as its factorization.

21041424251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 717721.

The product of its (nonzero) digits is 2560, while the sum is 26.

Adding to 21041424251 its reverse (15242414012), we get a palindrome (36283838263).

The spelling of 21041424251 in words is "twenty-one billion, forty-one million, four hundred twenty-four thousand, two hundred fifty-one".