1657424921 has 2 divisors, whose sum is σ = 1657424922. Its totient is φ = 1657424920.

The previous prime is 1657424917. The next prime is 1657424927. The reversal of 1657424921 is 1294247561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 953265625 + 704159296 = 30875^2 + 26536^2 .

It is an emirp because it is prime and its reverse (1294247561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1657424921 - 2² = 1657424917 is a prime.

It is not a weakly prime, because it can be changed into another prime (1657424927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828712460 + 828712461.

It is an arithmetic number, because the mean of its divisors is an integer number (828712461).

Almost surely, 2^1657424921 is an apocalyptic number.

It is an amenable number.

1657424921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1657424921 is an equidigital number, since it uses as much as digits as its factorization.

1657424921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 41.

The square root of 1657424921 is about 40711.4838958248. The cubic root of 1657424921 is about 1183.4355781697.

The spelling of 1657424921 in words is "one billion, six hundred fifty-seven million, four hundred twenty-four thousand, nine hundred twenty-one".