21101355251 has 8 divisors (see below), whose sum is σ = 21481963440. Its totient is φ = 20721512448.

The previous prime is 21101355211. The next prime is 21101355257. The reversal of 21101355251 is 15255310112.

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 21101355251 - 2²² = 21097160947 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 21101355251.

It is not an unprimeable number, because it can be changed into a prime (21101355257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135566 + ... + 246131.

It is an arithmetic number, because the mean of its divisors is an integer number (2685245430).

Almost surely, 2^21101355251 is an apocalyptic number.

21101355251 is a deficient number, since it is larger than the sum of its proper divisors (380608189).

21101355251 is an equidigital number, since it uses as much as digits as its factorization.

21101355251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382693.

The product of its (nonzero) digits is 1500, while the sum is 26.

Adding to 21101355251 its reverse (15255310112), we get a palindrome (36356665363).

The spelling of 21101355251 in words is "twenty-one billion, one hundred one million, three hundred fifty-five thousand, two hundred fifty-one".