21551352601 has 4 divisors (see below), whose sum is σ = 21552015204. Its totient is φ = 21550690000.

The previous prime is 21551352587. The next prime is 21551352607. The reversal of 21551352601 is 10625315512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4063935001 + 17487417600 = 63749^2 + 132240^2 .

It is a cyclic number.

It is not a de Polignac number, because 21551352601 - 2¹¹ = 21551350553 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21551352607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279850 + ... + 348451.

It is an arithmetic number, because the mean of its divisors is an integer number (5388003801).

Almost surely, 2^21551352601 is an apocalyptic number.

It is an amenable number.

21551352601 is a deficient number, since it is larger than the sum of its proper divisors (662603).

21551352601 is an equidigital number, since it uses as much as digits as its factorization.

21551352601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662602.

The product of its (nonzero) digits is 9000, while the sum is 31.

The spelling of 21551352601 in words is "twenty-one billion, five hundred fifty-one million, three hundred fifty-two thousand, six hundred one".