661542562201 has 8 divisors (see below), whose sum is σ = 665799824520. Its totient is φ = 657285852288.

The previous prime is 661542562151. The next prime is 661542562211. The reversal of 661542562201 is 102265245166.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 130248810000 + 531293752201 = 360900^2 + 728899^2 .

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 661542562201 - 2¹³ = 661542554009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661542562211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2416155 + ... + 2675983.

It is an arithmetic number, because the mean of its divisors is an integer number (83224978065).

Almost surely, 2^661542562201 is an apocalyptic number.

It is an amenable number.

661542562201 is a deficient number, since it is larger than the sum of its proper divisors (4257262319).

661542562201 is a wasteful number, since it uses less digits than its factorization.

661542562201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276203.

The product of its (nonzero) digits is 172800, while the sum is 40.

The spelling of 661542562201 in words is "six hundred sixty-one billion, five hundred forty-two million, five hundred sixty-two thousand, two hundred one".