1066721631 has 8 divisors (see below), whose sum is σ = 1425409584. Its totient is φ = 709590720.

The previous prime is 1066721629. The next prime is 1066721647. The reversal of 1066721631 is 1361276601.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1066721631 - 2¹ = 1066721629 is a prime.

It is a super-2 number, since 2×1066721631² = 2275790076086600322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1066721592 and 1066721601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1066721431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 387660 + ... + 390401.

It is an arithmetic number, because the mean of its divisors is an integer number (178176198).

Almost surely, 2^1066721631 is an apocalyptic number.

1066721631 is a deficient number, since it is larger than the sum of its proper divisors (358687953).

1066721631 is an equidigital number, since it uses as much as digits as its factorization.

1066721631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778521.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 1066721631 is about 32660.7046923363. The cubic root of 1066721631 is about 1021.7634594263.

The spelling of 1066721631 in words is "one billion, sixty-six million, seven hundred twenty-one thousand, six hundred thirty-one".