661051505001 has 4 divisors (see below), whose sum is σ = 881402006672. Its totient is φ = 440701003332.

The previous prime is 661051504973. The next prime is 661051505003. The reversal of 661051505001 is 100505150166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 661051505001 - 2⁵ = 661051504969 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661051505001.

It is not an unprimeable number, because it can be changed into a prime (661051505003) 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, 110175250831 + ... + 110175250836.

It is an arithmetic number, because the mean of its divisors is an integer number (220350501668).

Almost surely, 2^661051505001 is an apocalyptic number.

It is an amenable number.

661051505001 is a deficient number, since it is larger than the sum of its proper divisors (220350501671).

661051505001 is a wasteful number, since it uses less digits than its factorization.

661051505001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220350501670.

The product of its (nonzero) digits is 4500, while the sum is 30.

Adding to 661051505001 its reverse (100505150166), we get a palindrome (761556655167).

The spelling of 661051505001 in words is "six hundred sixty-one billion, fifty-one million, five hundred five thousand, one".