661550607 has 12 divisors (see below), whose sum is σ = 1005866680. Its totient is φ = 417821328.

The previous prime is 661550579. The next prime is 661550629. The reversal of 661550607 is 706055166.

It is a happy number.

It is not a de Polignac number, because 661550607 - 2¹⁰ = 661549583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661550107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1934188 + ... + 1934529.

Almost surely, 2^661550607 is an apocalyptic number.

661550607 is a deficient number, since it is larger than the sum of its proper divisors (344316073).

661550607 is a wasteful number, since it uses less digits than its factorization.

661550607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3868742 (or 3868739 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 36.

The square root of 661550607 is about 25720.6261004665. The cubic root of 661550607 is about 871.3400790613.

The spelling of 661550607 in words is "six hundred sixty-one million, five hundred fifty thousand, six hundred seven".