6605981 has 4 divisors (see below), whose sum is σ = 6617472. Its totient is φ = 6594492.

The previous prime is 6605971. The next prime is 6605983. The reversal of 6605981 is 1895066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6605981 - 2⁶ = 6605917 is a prime.

It is a super-2 number, since 2×6605981² = 87277969944722, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6605983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4835 + ... + 6048.

It is an arithmetic number, because the mean of its divisors is an integer number (1654368).

Almost surely, 2^6605981 is an apocalyptic number.

It is an amenable number.

6605981 is a deficient number, since it is larger than the sum of its proper divisors (11491).

6605981 is a wasteful number, since it uses less digits than its factorization.

6605981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11490.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 6605981 is about 2570.2103026795. The cubic root of 6605981 is about 187.6343901717.

Subtracting from 6605981 its reverse (1895066), we obtain a triangular number (4710915 = T₃₀₆₉).

The spelling of 6605981 in words is "six million, six hundred five thousand, nine hundred eighty-one".