5661990 has 48 divisors (see below), whose sum is σ = 15011568. Its totient is φ = 1480128.

The previous prime is 5661973. The next prime is 5661991. The reversal of 5661990 is 991665.

5661990 is a `hidden beast` number, since 566 + 1 + 9 + 90 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5661991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4177 + ... + 5363.

It is an arithmetic number, because the mean of its divisors is an integer number (312741).

Almost surely, 2^5661990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 5661990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7505784).

5661990 is an abundant number, since it is smaller than the sum of its proper divisors (9349578).

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

5661990 is a wasteful number, since it uses less digits than its factorization.

5661990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1253 (or 1250 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 5661990 is about 2379.4936436141. The cubic root of 5661990 is about 178.2336493195.

It can be divided in two parts, 566 and 1990, that added together give a triangular number (2556 = T₇₁).

The spelling of 5661990 in words is "five million, six hundred sixty-one thousand, nine hundred ninety".