201521570551 has 4 divisors (see below), whose sum is σ = 230310366352. Its totient is φ = 172732774752.

The previous prime is 201521570479. The next prime is 201521570557. The reversal of 201521570551 is 155075125102.

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

It is a cyclic number.

It is not a de Polignac number, because 201521570551 - 2¹⁷ = 201521439479 is a prime.

It is a super-2 number, since 2×201521570551² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201521570557) 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, 14394397890 + ... + 14394397903.

It is an arithmetic number, because the mean of its divisors is an integer number (57577591588).

Almost surely, 2^201521570551 is an apocalyptic number.

201521570551 is a deficient number, since it is larger than the sum of its proper divisors (28788795801).

201521570551 is an equidigital number, since it uses as much as digits as its factorization.

201521570551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28788795800.

The product of its (nonzero) digits is 17500, while the sum is 34.

Adding to 201521570551 its reverse (155075125102), we get a palindrome (356596695653).

The spelling of 201521570551 in words is "two hundred one billion, five hundred twenty-one million, five hundred seventy thousand, five hundred fifty-one".