1981653 has 8 divisors (see below), whose sum is σ = 2706816. Its totient is φ = 1288800.

The previous prime is 1981649. The next prime is 1981663. The reversal of 1981653 is 3561891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1981653 - 2² = 1981649 is a prime.

It is a super-2 number, since 2×1981653² = 7853897224818, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981663) 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 7 ways as a sum of consecutive naturals, for example, 7933 + ... + 8178.

It is an arithmetic number, because the mean of its divisors is an integer number (338352).

2^1981653 is an apocalyptic number.

It is an amenable number.

1981653 is a deficient number, since it is larger than the sum of its proper divisors (725163).

1981653 is a wasteful number, since it uses less digits than its factorization.

1981653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16155.

The product of its digits is 6480, while the sum is 33.

The square root of 1981653 is about 1407.7119733809. The cubic root of 1981653 is about 125.6056580206.

It can be divided in two parts, 198165 and 3, that multiplied together give a palindrome (594495).

The spelling of 1981653 in words is "one million, nine hundred eighty-one thousand, six hundred fifty-three".