1561801 has 2 divisors, whose sum is σ = 1561802. Its totient is φ = 1561800.

The previous prime is 1561759. The next prime is 1561817. The reversal of 1561801 is 1081651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1440000 + 121801 = 1200^2 + 349^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561801 - 2⁷ = 1561673 is a prime.

It is not a weakly prime, because it can be changed into another prime (1561891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780900 + 780901.

It is an arithmetic number, because the mean of its divisors is an integer number (780901).

2^1561801 is an apocalyptic number.

It is an amenable number.

1561801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561801 is an equidigital number, since it uses as much as digits as its factorization.

1561801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 22.

The square root of 1561801 is about 1249.7203687225. The cubic root of 1561801 is about 116.0224144162.

It can be divided in two parts, 15 and 61801, that added together give a palindrome (61816).

The spelling of 1561801 in words is "one million, five hundred sixty-one thousand, eight hundred one".