1616981 has 4 divisors (see below), whose sum is σ = 1621452. Its totient is φ = 1612512.

The previous prime is 1616963. The next prime is 1616983. The reversal of 1616981 is 1896161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 586756 + 1030225 = 766^2 + 1015^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1616981 is a prime.

It is a super-2 number, since 2×1616981² = 5229255108722, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1616983) 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, 1640 + ... + 2433.

It is an arithmetic number, because the mean of its divisors is an integer number (405363).

2^1616981 is an apocalyptic number.

It is an amenable number.

1616981 is a deficient number, since it is larger than the sum of its proper divisors (4471).

1616981 is an equidigital number, since it uses as much as digits as its factorization.

1616981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4470.

The product of its digits is 2592, while the sum is 32.

The square root of 1616981 is about 1271.6056778735. The cubic root of 1616981 is about 117.3730271678.

The spelling of 1616981 in words is "one million, six hundred sixteen thousand, nine hundred eighty-one".