661511101551 has 16 divisors (see below), whose sum is σ = 904523682048. Its totient is φ = 429776683200.

The previous prime is 661511101523. The next prime is 661511101561. The reversal of 661511101551 is 155101115166.

It is not a de Polignac number, because 661511101551 - 2¹⁰ = 661511100527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661511101561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2853235 + ... + 3076356.

It is an arithmetic number, because the mean of its divisors is an integer number (56532730128).

Almost surely, 2^661511101551 is an apocalyptic number.

661511101551 is a deficient number, since it is larger than the sum of its proper divisors (243012580497).

661511101551 is a wasteful number, since it uses less digits than its factorization.

661511101551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5930542.

The product of its (nonzero) digits is 4500, while the sum is 33.

The spelling of 661511101551 in words is "six hundred sixty-one billion, five hundred eleven million, one hundred one thousand, five hundred fifty-one".