7857990 has 48 divisors (see below), whose sum is σ = 23351328. Its totient is φ = 1795968.

The previous prime is 7857989. The next prime is 7858003. The reversal of 7857990 is 997587.

7857990 is a `hidden beast` number, since 78 + 579 + 9 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5607 + ... + 6866.

It is an arithmetic number, because the mean of its divisors is an integer number (486486).

Almost surely, 2^7857990 is an apocalyptic number.

7857990 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

7857990 is an abundant number, since it is smaller than the sum of its proper divisors (15493338).

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

7857990 is a wasteful number, since it uses less digits than its factorization.

7857990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12493 (or 12490 counting only the distinct ones).

The product of its (nonzero) digits is 158760, while the sum is 45.

The square root of 7857990 is about 2803.2106592263. The cubic root of 7857990 is about 198.8095110742.

The spelling of 7857990 in words is "seven million, eight hundred fifty-seven thousand, nine hundred ninety".