1665256220 has 24 divisors (see below), whose sum is σ = 3529125600. Its totient is φ = 659990592.

The previous prime is 1665256213. The next prime is 1665256249. The reversal of 1665256220 is 226525661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 379760 + ... + 384119.

It is an arithmetic number, because the mean of its divisors is an integer number (147046900).

Almost surely, 2^1665256220 is an apocalyptic number.

1665256220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1665256220 is an abundant number, since it is smaller than the sum of its proper divisors (1863869380).

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

1665256220 is a wasteful number, since it uses less digits than its factorization.

1665256220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763997 (or 763995 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 1665256220 is about 40807.5510169380. The cubic root of 1665256220 is about 1185.2965532194.

The spelling of 1665256220 in words is "one billion, six hundred sixty-five million, two hundred fifty-six thousand, two hundred twenty".