1620961 has 2 divisors, whose sum is σ = 1620962. Its totient is φ = 1620960.

The previous prime is 1620929. The next prime is 1620973. The reversal of 1620961 is 1690261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1600225 + 20736 = 1265^2 + 144^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620961 - 2⁵ = 1620929 is a prime.

It is not a weakly prime, because it can be changed into another prime (1620161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810480 + 810481.

It is an arithmetic number, because the mean of its divisors is an integer number (810481).

2^1620961 is an apocalyptic number.

It is an amenable number.

1620961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620961 is an equidigital number, since it uses as much as digits as its factorization.

1620961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 1620961 is about 1273.1696666195. The cubic root of 1620961 is about 117.4692480260.

The spelling of 1620961 in words is "one million, six hundred twenty thousand, nine hundred sixty-one".