1661057837501 has 2 divisors, whose sum is σ = 1661057837502. Its totient is φ = 1661057837500.

The previous prime is 1661057837489. The next prime is 1661057837507. The reversal of 1661057837501 is 1057387501661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1114861456900 + 546196380601 = 1055870^2 + 739051^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661057837501 - 2⁶ = 1661057837437 is a prime.

It is a super-2 number, since 2×1661057837501² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1661057837501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661057837507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830528918750 + 830528918751.

It is an arithmetic number, because the mean of its divisors is an integer number (830528918751).

Almost surely, 2^{1661057837501} is an apocalyptic number.

It is an amenable number.

1661057837501 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661057837501 is an equidigital number, since it uses as much as digits as its factorization.

1661057837501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1058400, while the sum is 50.

The spelling of 1661057837501 in words is "one trillion, six hundred sixty-one billion, fifty-seven million, eight hundred thirty-seven thousand, five hundred one".