1820723440 has 20 divisors (see below), whose sum is σ = 4233182184. Its totient is φ = 728289344.

The previous prime is 1820723407. The next prime is 1820723453. The reversal of 1820723440 is 443270281.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11379442 + ... + 11379601.

Almost surely, 2^1820723440 is an apocalyptic number.

1820723440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1820723440 is an abundant number, since it is smaller than the sum of its proper divisors (2412458744).

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

1820723440 is a wasteful number, since it uses less digits than its factorization.

1820723440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22759056 (or 22759050 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 1820723440 is about 42669.9360205754. The cubic root of 1820723440 is about 1221.0908991934.

The spelling of 1820723440 in words is "one billion, eight hundred twenty million, seven hundred twenty-three thousand, four hundred forty".