1979990 has 32 divisors (see below), whose sum is σ = 3978720. Its totient is φ = 705024.

The previous prime is 1979947. The next prime is 1979993. The reversal of 1979990 is 999791.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1979993) 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, 2924 + ... + 3536.

It is an arithmetic number, because the mean of its divisors is an integer number (124335).

2^1979990 is an apocalyptic number.

1979990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1979990 is an abundant number, since it is smaller than the sum of its proper divisors (1998730).

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

1979990 is a wasteful number, since it uses less digits than its factorization.

1979990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656.

The product of its (nonzero) digits is 45927, while the sum is 44.

The square root of 1979990 is about 1407.1211745973. The cubic root of 1979990 is about 125.5705121655.

It can be divided in two parts, 1979 and 990, that multiplied together give a triangular number (1959210 = T₁₉₇₉).

The spelling of 1979990 in words is "one million, nine hundred seventy-nine thousand, nine hundred ninety".