661576152805 has 4 divisors (see below), whose sum is σ = 793891383372. Its totient is φ = 529260922240.

The previous prime is 661576152803. The next prime is 661576152821. The reversal of 661576152805 is 508251675166.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 79343059041 + 582233093764 = 281679^2 + 763042^2 .

It is not a de Polignac number, because 661576152805 - 2¹ = 661576152803 is a prime.

It is a super-3 number, since 3×661576152805³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661576152803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66157615276 + ... + 66157615285.

It is an arithmetic number, because the mean of its divisors is an integer number (198472845843).

Almost surely, 2^661576152805 is an apocalyptic number.

It is an amenable number.

661576152805 is a deficient number, since it is larger than the sum of its proper divisors (132315230567).

661576152805 is a wasteful number, since it uses less digits than its factorization.

661576152805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132315230566.

The product of its (nonzero) digits is 3024000, while the sum is 52.

The spelling of 661576152805 in words is "six hundred sixty-one billion, five hundred seventy-six million, one hundred fifty-two thousand, eight hundred five".