1661655101 has 2 divisors, whose sum is σ = 1661655102. Its totient is φ = 1661655100.

The previous prime is 1661655077. The next prime is 1661655133. The reversal of 1661655101 is 1015561661.

It is an a-pointer prime, because the next prime (1661655133) can be obtained adding 1661655101 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1646249476 + 15405625 = 40574^2 + 3925^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661655101 - 2¹⁰ = 1661654077 is a prime.

It is a super-2 number, since 2×1661655101² = 5522195349358640402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1651655101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830827550 + 830827551.

It is an arithmetic number, because the mean of its divisors is an integer number (830827551).

Almost surely, 2^1661655101 is an apocalyptic number.

It is an amenable number.

1661655101 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661655101 is an equidigital number, since it uses as much as digits as its factorization.

1661655101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1661655101 is about 40763.4039427524. The cubic root of 1661655101 is about 1184.4415347561.

It can be divided in two parts, 16616 and 55101, that added together give a palindrome (71717).

The spelling of 1661655101 in words is "one billion, six hundred sixty-one million, six hundred fifty-five thousand, one hundred one".