661121507 has 8 divisors (see below), whose sum is σ = 672031296. Its totient is φ = 650261952.

The previous prime is 661121471. The next prime is 661121537. The reversal of 661121507 is 705121166.

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

It is a cyclic number.

It is not a de Polignac number, because 661121507 - 2¹⁰ = 661120483 is a prime.

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 661121507.

It is not an unprimeable number, because it can be changed into a prime (661121537) 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, 14453 + ... + 39129.

It is an arithmetic number, because the mean of its divisors is an integer number (84003912).

Almost surely, 2^661121507 is an apocalyptic number.

661121507 is a deficient number, since it is larger than the sum of its proper divisors (10909789).

661121507 is a wasteful number, since it uses less digits than its factorization.

661121507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25117.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 661121507 is about 25712.2831930577. The cubic root of 661121507 is about 871.1516465655.

The spelling of 661121507 in words is "six hundred sixty-one million, one hundred twenty-one thousand, five hundred seven".