1661201357 has 2 divisors, whose sum is σ = 1661201358. Its totient is φ = 1661201356.

The previous prime is 1661201341. The next prime is 1661201401. The reversal of 1661201357 is 7531021661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1647466921 + 13734436 = 40589^2 + 3706^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661201357 - 2⁴ = 1661201341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661201957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830600678 + 830600679.

It is an arithmetic number, because the mean of its divisors is an integer number (830600679).

Almost surely, 2^1661201357 is an apocalyptic number.

It is an amenable number.

1661201357 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661201357 is an equidigital number, since it uses as much as digits as its factorization.

1661201357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 1661201357 is about 40757.8379824053. The cubic root of 1661201357 is about 1184.3337141128. Note that the first 3 decimals are identical.

The spelling of 1661201357 in words is "one billion, six hundred sixty-one million, two hundred one thousand, three hundred fifty-seven".