1666306631025 has 81 divisors (see below), whose sum is σ = 3051058595403. Its totient is φ = 869313391200.

The previous prime is 1666306630999. The next prime is 1666306631071. The reversal of 1666306631025 is 5201366036661.

The square root of 1666306631025 is 1290855.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 599870387169 + 1066436243856 = 774513^2 + 1032684^2 .

It is not a de Polignac number, because 1666306631025 - 2²⁹ = 1665769760113 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 910051860 + ... + 910053690.

Almost surely, 2^{1666306631025} is an apocalyptic number.

1666306631025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1666306631025 is the 1290855-th square number.

1666306631025 is the 645428-th centered octagonal number.

It is an amenable number.

1666306631025 is a deficient number, since it is larger than the sum of its proper divisors (1384751964378).

1666306631025 is an frugal number, since it uses more digits than its factorization.

1666306631025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3772 (or 1886 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The spelling of 1666306631025 in words is "one trillion, six hundred sixty-six billion, three hundred six million, six hundred thirty-one thousand, twenty-five".