5615981 has 4 divisors (see below), whose sum is σ = 6418272. Its totient is φ = 4813692.

The previous prime is 5615977. The next prime is 5616011. The reversal of 5615981 is 1895165.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1895165 = 5 ⋅379033.

It is a cyclic number.

It is not a de Polignac number, because 5615981 - 2² = 5615977 is a prime.

It is a super-2 number, since 2×5615981² = 63078485184722, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5615081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 401135 + ... + 401148.

It is an arithmetic number, because the mean of its divisors is an integer number (1604568).

Almost surely, 2^5615981 is an apocalyptic number.

It is an amenable number.

5615981 is a deficient number, since it is larger than the sum of its proper divisors (802291).

5615981 is an equidigital number, since it uses as much as digits as its factorization.

5615981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 802290.

The product of its digits is 10800, while the sum is 35.

The square root of 5615981 is about 2369.8061102124. The cubic root of 5615981 is about 177.7495636504.

The spelling of 5615981 in words is "five million, six hundred fifteen thousand, nine hundred eighty-one".