21601451051 has 4 divisors (see below), whose sum is σ = 21967577400. Its totient is φ = 21235324704.

The previous prime is 21601451041. The next prime is 21601451059. The reversal of 21601451051 is 15015410612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21601451051 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 21601451051.

It is not an unprimeable number, because it can be changed into a prime (21601451059) 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 3 ways as a sum of consecutive naturals, for example, 183063086 + ... + 183063203.

It is an arithmetic number, because the mean of its divisors is an integer number (5491894350).

Almost surely, 2^21601451051 is an apocalyptic number.

21601451051 is a deficient number, since it is larger than the sum of its proper divisors (366126349).

21601451051 is an equidigital number, since it uses as much as digits as its factorization.

21601451051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366126348.

The product of its (nonzero) digits is 1200, while the sum is 26.

Adding to 21601451051 its reverse (15015410612), we get a palindrome (36616861663).

The spelling of 21601451051 in words is "twenty-one billion, six hundred one million, four hundred fifty-one thousand, fifty-one".