1651663 has 4 divisors (see below), whose sum is σ = 1778728. Its totient is φ = 1524600.

The previous prime is 1651621. The next prime is 1651667. The reversal of 1651663 is 3661561.

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

It is a cyclic number.

It is not a de Polignac number, because 1651663 - 2⁹ = 1651151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1651667) 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, 63513 + ... + 63538.

It is an arithmetic number, because the mean of its divisors is an integer number (444682).

2^1651663 is an apocalyptic number.

1651663 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1651663 is a deficient number, since it is larger than the sum of its proper divisors (127065).

1651663 is a wasteful number, since it uses less digits than its factorization.

1651663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127064.

The product of its digits is 3240, while the sum is 28.

The square root of 1651663 is about 1285.1704167152. The cubic root of 1651663 is about 118.2062609117.

The spelling of 1651663 in words is "one million, six hundred fifty-one thousand, six hundred sixty-three".