820187551 has 4 divisors (see below), whose sum is σ = 820351872. Its totient is φ = 820023232.

The previous prime is 820187539. The next prime is 820187603. The reversal of 820187551 is 155781028.

820187551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 820187551 - 2²⁵ = 786633119 is a prime.

It is a super-3 number, since 3×820187551³ (a number of 28 digits) contains 333 as substring.

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 820187551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820182551) 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, 74431 + ... + 84736.

It is an arithmetic number, because the mean of its divisors is an integer number (205087968).

Almost surely, 2^820187551 is an apocalyptic number.

820187551 is a deficient number, since it is larger than the sum of its proper divisors (164321).

820187551 is a wasteful number, since it uses less digits than its factorization.

820187551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164320.

The product of its (nonzero) digits is 22400, while the sum is 37.

The square root of 820187551 is about 28638.9167218315. The cubic root of 820187551 is about 936.0615169926.

The spelling of 820187551 in words is "eight hundred twenty million, one hundred eighty-seven thousand, five hundred fifty-one".