821012332551 has 4 divisors (see below), whose sum is σ = 1094683110072. Its totient is φ = 547341555032.

The previous prime is 821012332499. The next prime is 821012332573. The reversal of 821012332551 is 155233210128.

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 821012332551 - 2⁹ = 821012332039 is a prime.

It is a super-2 number, since 2×821012332551² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821012331551) 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, 136835388756 + ... + 136835388761.

It is an arithmetic number, because the mean of its divisors is an integer number (273670777518).

Almost surely, 2^821012332551 is an apocalyptic number.

821012332551 is a deficient number, since it is larger than the sum of its proper divisors (273670777521).

821012332551 is a wasteful number, since it uses less digits than its factorization.

821012332551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273670777520.

The product of its (nonzero) digits is 14400, while the sum is 33.

Adding to 821012332551 its reverse (155233210128), we get a palindrome (976245542679).

The spelling of 821012332551 in words is "eight hundred twenty-one billion, twelve million, three hundred thirty-two thousand, five hundred fifty-one".