21154303251 has 8 divisors (see below), whose sum is σ = 31339708560. Its totient is φ = 14102868816.

The previous prime is 21154303237. The next prime is 21154303279. The reversal of 21154303251 is 15230345112.

It is not a de Polignac number, because 21154303251 - 2⁷ = 21154303123 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 783492713 = 21154303251 / (2 + 1 + 1 + 5 + 4 + 3 + 0 + 3 + 2 + 5 + 1).

It is not an unprimeable number, because it can be changed into a prime (21154303351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 391746330 + ... + 391746383.

It is an arithmetic number, because the mean of its divisors is an integer number (3917463570).

Almost surely, 2^21154303251 is an apocalyptic number.

21154303251 is a deficient number, since it is larger than the sum of its proper divisors (10185405309).

21154303251 is an equidigital number, since it uses as much as digits as its factorization.

21154303251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783492722 (or 783492716 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

Adding to 21154303251 its reverse (15230345112), we get a palindrome (36384648363).

The spelling of 21154303251 in words is "twenty-one billion, one hundred fifty-four million, three hundred three thousand, two hundred fifty-one".