1820377840 has 40 divisors (see below), whose sum is σ = 4455138960. Its totient is φ = 689826816.

The previous prime is 1820377831. The next prime is 1820377841. The reversal of 1820377840 is 487730281.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 1820377793 and 1820377802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820377841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 597289 + ... + 600328.

It is an arithmetic number, because the mean of its divisors is an integer number (111378474).

Almost surely, 2^1820377840 is an apocalyptic number.

1820377840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1820377840 is an abundant number, since it is smaller than the sum of its proper divisors (2634761120).

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

1820377840 is a wasteful number, since it uses less digits than its factorization.

1820377840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1197649 (or 1197643 counting only the distinct ones).

The product of its (nonzero) digits is 75264, while the sum is 40.

The square root of 1820377840 is about 42665.8861386940. The cubic root of 1820377840 is about 1221.0136339867.

The spelling of 1820377840 in words is "one billion, eight hundred twenty million, three hundred seventy-seven thousand, eight hundred forty".