1821820815 has 96 divisors (see below), whose sum is σ = 3405782016. Its totient is φ = 933586560.

The previous prime is 1821820813. The next prime is 1821820853. The reversal of 1821820815 is 5180281281.

It is not a de Polignac number, because 1821820815 - 2¹ = 1821820813 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1821820815.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821820811) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3483144 + ... + 3483666.

It is an arithmetic number, because the mean of its divisors is an integer number (35476896).

Almost surely, 2^1821820815 is an apocalyptic number.

1821820815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1821820815 is a deficient number, since it is larger than the sum of its proper divisors (1583961201).

1821820815 is an equidigital number, since it uses as much as digits as its factorization.

1821820815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651 (or 639 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 36.

The square root of 1821820815 is about 42682.7929615671. The cubic root of 1821820815 is about 1221.3361726701.

The spelling of 1821820815 in words is "one billion, eight hundred twenty-one million, eight hundred twenty thousand, eight hundred fifteen".