1553861 has 4 divisors (see below), whose sum is σ = 1557132. Its totient is φ = 1550592.

The previous prime is 1553837. The next prime is 1553869. The reversal of 1553861 is 1683551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1683551 = 149 ⋅11299.

It can be written as a sum of positive squares in 2 ways, for example, as 1223236 + 330625 = 1106^2 + 575^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1553861 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 (1553869) 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, 770 + ... + 1923.

It is an arithmetic number, because the mean of its divisors is an integer number (389283).

2^1553861 is an apocalyptic number.

It is an amenable number.

1553861 is a deficient number, since it is larger than the sum of its proper divisors (3271).

1553861 is an equidigital number, since it uses as much as digits as its factorization.

1553861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3270.

The product of its digits is 3600, while the sum is 29.

The square root of 1553861 is about 1246.5396102812. The cubic root of 1553861 is about 115.8254658264.

The spelling of 1553861 in words is "one million, five hundred fifty-three thousand, eight hundred sixty-one".