1657121 has 2 divisors, whose sum is σ = 1657122. Its totient is φ = 1657120.

The previous prime is 1657099. The next prime is 1657129. The reversal of 1657121 is 1217561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1079521 + 577600 = 1039^2 + 760^2 .

It is an emirp because it is prime and its reverse (1217561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1657121 - 2¹⁸ = 1394977 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1657129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828560 + 828561.

It is an arithmetic number, because the mean of its divisors is an integer number (828561).

2^1657121 is an apocalyptic number.

It is an amenable number.

1657121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1657121 is an equidigital number, since it uses as much as digits as its factorization.

1657121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 420, while the sum is 23.

The square root of 1657121 is about 1287.2921191400. The cubic root of 1657121 is about 118.3363238460.

It can be divided in two parts, 16 and 57121, that multiplied together give a square (913936 = 956²).

The spelling of 1657121 in words is "one million, six hundred fifty-seven thousand, one hundred twenty-one".