1617981 has 16 divisors (see below), whose sum is σ = 2280960. Its totient is φ = 1018160.

The previous prime is 1617977. The next prime is 1617989. The reversal of 1617981 is 1897161.

It is a cyclic number.

It is not a de Polignac number, because 1617981 - 2² = 1617977 is a prime.

It is a super-2 number, since 2×1617981² = 5235725032722, which contains 22 as substring.

Its product of digits (3024) is a multiple of the sum of its prime divisors (336).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1617989) 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, 8950 + ... + 9128.

It is an arithmetic number, because the mean of its divisors is an integer number (142560).

2^1617981 is an apocalyptic number.

It is an amenable number.

1617981 is a deficient number, since it is larger than the sum of its proper divisors (662979).

1617981 is a wasteful number, since it uses less digits than its factorization.

1617981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336.

The product of its digits is 3024, while the sum is 33.

The square root of 1617981 is about 1271.9988207542. The cubic root of 1617981 is about 117.3972181013.

The spelling of 1617981 in words is "one million, six hundred seventeen thousand, nine hundred eighty-one".