661561606 has 8 divisors (see below), whose sum is σ = 992512944. Its totient is φ = 330723960.

The previous prime is 661561583. The next prime is 661561651. The reversal of 661561606 is 606165166.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11970 + ... + 38293.

It is an arithmetic number, because the mean of its divisors is an integer number (124064118).

Almost surely, 2^661561606 is an apocalyptic number.

661561606 is a deficient number, since it is larger than the sum of its proper divisors (330951338).

661561606 is a wasteful number, since it uses less digits than its factorization.

661561606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56846.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 661561606 is about 25720.8399163013. The cubic root of 661561606 is about 871.3449080274.

The spelling of 661561606 in words is "six hundred sixty-one million, five hundred sixty-one thousand, six hundred six".