1661685505151 has 32 divisors (see below), whose sum is σ = 1954012769280. Its totient is φ = 1383476661504.

The previous prime is 1661685505057. The next prime is 1661685505157. The reversal of 1661685505151 is 1515055861661.

It is not a de Polignac number, because 1661685505151 - 2¹⁴ = 1661685488767 is a prime.

It is a super-2 number, since 2×1661685505151² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661685505151.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661685505157) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57705065 + ... + 57733853.

It is an arithmetic number, because the mean of its divisors is an integer number (61062899040).

Almost surely, 2^{1661685505151} is an apocalyptic number.

1661685505151 is a deficient number, since it is larger than the sum of its proper divisors (292327264129).

1661685505151 is a wasteful number, since it uses less digits than its factorization.

1661685505151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29895.

The product of its (nonzero) digits is 1080000, while the sum is 50.

The spelling of 1661685505151 in words is "one trillion, six hundred sixty-one billion, six hundred eighty-five million, five hundred five thousand, one hundred fifty-one".