661001011 has 4 divisors (see below), whose sum is σ = 721092024. Its totient is φ = 600910000.

The previous prime is 661000999. The next prime is 661001027. The reversal of 661001011 is 110100166.

661001011 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661001011 - 2¹¹ = 660998963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661001111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30045490 + ... + 30045511.

It is an arithmetic number, because the mean of its divisors is an integer number (180273006).

Almost surely, 2^661001011 is an apocalyptic number.

661001011 is a deficient number, since it is larger than the sum of its proper divisors (60091013).

661001011 is a wasteful number, since it uses less digits than its factorization.

661001011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60091012.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 661001011 is about 25709.9399260286. The cubic root of 661001011 is about 871.0987179859.

Adding to 661001011 its reverse (110100166), we get a palindrome (771101177).

The spelling of 661001011 in words is "six hundred sixty-one million, one thousand, eleven".