66561602 has 4 divisors (see below), whose sum is σ = 99842406. Its totient is φ = 33280800.

The previous prime is 66561571. The next prime is 66561611. The reversal of 66561602 is 20616566.

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

It can be written as a sum of positive squares in only one way, i.e., 53158681 + 13402921 = 7291^2 + 3661^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16640399 + ... + 16640402.

Almost surely, 2^66561602 is an apocalyptic number.

66561602 is a deficient number, since it is larger than the sum of its proper divisors (33280804).

66561602 is a wasteful number, since it uses less digits than its factorization.

66561602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33280803.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 66561602 is about 8158.5294017979. The cubic root of 66561602 is about 405.2670128669.

The spelling of 66561602 in words is "sixty-six million, five hundred sixty-one thousand, six hundred two".