661101551 has 8 divisors (see below), whose sum is σ = 722304000. Its totient is φ = 600082840.

The previous prime is 661101547. The next prime is 661101569. The reversal of 661101551 is 155101166.

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 661101551 - 2² = 661101547 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661101551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661101541) 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, 38351 + ... + 52848.

It is an arithmetic number, because the mean of its divisors is an integer number (90288000).

Almost surely, 2^661101551 is an apocalyptic number.

661101551 is a deficient number, since it is larger than the sum of its proper divisors (61202449).

661101551 is a wasteful number, since it uses less digits than its factorization.

661101551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91869.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 661101551 is about 25711.8951265752. The cubic root of 661101551 is about 871.1428812190.

The spelling of 661101551 in words is "six hundred sixty-one million, one hundred one thousand, five hundred fifty-one".