1821881772 has 36 divisors (see below), whose sum is σ = 4876214616. Its totient is φ = 571570560.

The previous prime is 1821881771. The next prime is 1821881777. The reversal of 1821881772 is 2771881281.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×1821881772² = 6638506382291719968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1821881771) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1487854 + ... + 1489077.

It is an arithmetic number, because the mean of its divisors is an integer number (135450406).

Almost surely, 2^1821881772 is an apocalyptic number.

1821881772 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1821881772 is an abundant number, since it is smaller than the sum of its proper divisors (3054332844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1821881772 is a wasteful number, since it uses less digits than its factorization.

1821881772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2976958 (or 2976953 counting only the distinct ones).

The product of its digits is 100352, while the sum is 45.

The square root of 1821881772 is about 42683.5070255479. The cubic root of 1821881772 is about 1221.3497942363.

The spelling of 1821881772 in words is "one billion, eight hundred twenty-one million, eight hundred eighty-one thousand, seven hundred seventy-two".