1821779890 has 32 divisors (see below), whose sum is σ = 3763376640. Its totient is φ = 621991104.

The previous prime is 1821779887. The next prime is 1821779899. The reversal of 1821779890 is 989771281.

It is not an unprimeable number, because it can be changed into a prime (1821779899) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37717 + ... + 71176.

It is an arithmetic number, because the mean of its divisors is an integer number (117605520).

Almost surely, 2^1821779890 is an apocalyptic number.

1821779890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1821779890 is an abundant number, since it is smaller than the sum of its proper divisors (1941596750).

1821779890 is a wasteful number, since it uses less digits than its factorization.

1821779890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109146.

The product of its (nonzero) digits is 508032, while the sum is 52.

The square root of 1821779890 is about 42682.3135502283. The cubic root of 1821779890 is about 1221.3270273219.

The spelling of 1821779890 in words is "one billion, eight hundred twenty-one million, seven hundred seventy-nine thousand, eight hundred ninety".