1651861 has 2 divisors, whose sum is σ = 1651862. Its totient is φ = 1651860.

The previous prime is 1651847. The next prime is 1651877. The reversal of 1651861 is 1681561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1188100 + 463761 = 1090^2 + 681^2 .

It is a cyclic number.

It is not a de Polignac number, because 1651861 - 2⁵ = 1651829 is a prime.

It is a Chen prime.

1651861 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1651801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 825930 + 825931.

It is an arithmetic number, because the mean of its divisors is an integer number (825931).

2^1651861 is an apocalyptic number.

It is an amenable number.

1651861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1651861 is an equidigital number, since it uses as much as digits as its factorization.

1651861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 28.

The square root of 1651861 is about 1285.2474469922. The cubic root of 1651861 is about 118.2109842127.

The spelling of 1651861 in words is "one million, six hundred fifty-one thousand, eight hundred sixty-one".