1662451788321 has 27 divisors (see below), whose sum is σ = 2424166618419. Its totient is φ = 1097854789392.

The previous prime is 1662451788299. The next prime is 1662451788331. The reversal of 1662451788321 is 1238871542661.

It is a happy number.

The square root of 1662451788321 is 1289361.

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

1662451788321 is a `hidden beast` number, since 1 + 6 + 6 + 24 + 517 + 8 + 83 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1158720920721 + 503730867600 = 1076439^2 + 709740^2 .

It is not a de Polignac number, because 1662451788321 - 2⁵ = 1662451788289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1662451788331) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 421619076 + ... + 421623018.

Almost surely, 2^{1662451788321} is an apocalyptic number.

1662451788321 is the 1289361-st square number.

1662451788321 is the 644681-st centered octagonal number.

It is an amenable number.

1662451788321 is a deficient number, since it is larger than the sum of its proper divisors (761714830098).

1662451788321 is an frugal number, since it uses more digits than its factorization.

1662451788321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8110 (or 4055 counting only the distinct ones).

The product of its digits is 3870720, while the sum is 54.

The spelling of 1662451788321 in words is "one trillion, six hundred sixty-two billion, four hundred fifty-one million, seven hundred eighty-eight thousand, three hundred twenty-one".