1651921 has 2 divisors, whose sum is σ = 1651922. Its totient is φ = 1651920.

The previous prime is 1651891. The next prime is 1651943. The reversal of 1651921 is 1291561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1354896 + 297025 = 1164^2 + 545^2 .

It is a cyclic number.

It is not a de Polignac number, because 1651921 - 2⁹ = 1651409 is a prime.

It is not a weakly prime, because it can be changed into another prime (1651961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 825960 + 825961.

It is an arithmetic number, because the mean of its divisors is an integer number (825961).

2^1651921 is an apocalyptic number.

It is an amenable number.

1651921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1651921 is an equidigital number, since it uses as much as digits as its factorization.

1651921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 25.

The square root of 1651921 is about 1285.2707885889. The cubic root of 1651921 is about 118.2124154415.

The spelling of 1651921 in words is "one million, six hundred fifty-one thousand, nine hundred twenty-one".