661015571062651 has 4 divisors (see below), whose sum is σ = 755446366928752. Its totient is φ = 566584775196552.

The previous prime is 661015571062643. The next prime is 661015571062709. The reversal of 661015571062651 is 156260175510166.

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

It is not a de Polignac number, because 661015571062651 - 2³ = 661015571062643 is a prime.

It is a super-2 number, since 2×661015571062651² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661015571062151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47215397933040 + ... + 47215397933053.

It is an arithmetic number, because the mean of its divisors is an integer number (188861591732188).

Almost surely, 2^{661015571062651} is an apocalyptic number.

661015571062651 is a deficient number, since it is larger than the sum of its proper divisors (94430795866101).

661015571062651 is an equidigital number, since it uses as much as digits as its factorization.

661015571062651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94430795866100.

The product of its (nonzero) digits is 2268000, while the sum is 52.

The spelling of 661015571062651 in words is "six hundred sixty-one trillion, fifteen billion, five hundred seventy-one million, sixty-two thousand, six hundred fifty-one".