661228071 has 16 divisors (see below), whose sum is σ = 1031019264. Its totient is φ = 369057024.

The previous prime is 661228067. The next prime is 661228091. The reversal of 661228071 is 170822166.

661228071 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 661228071 - 2² = 661228067 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661228021) 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, 365226 + ... + 367031.

It is an arithmetic number, because the mean of its divisors is an integer number (64438704).

Almost surely, 2^661228071 is an apocalyptic number.

661228071 is a deficient number, since it is larger than the sum of its proper divisors (369791193).

661228071 is a wasteful number, since it uses less digits than its factorization.

661228071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 732310.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 661228071 is about 25714.3553487152. The cubic root of 661228071 is about 871.1984500732.

The spelling of 661228071 in words is "six hundred sixty-one million, two hundred twenty-eight thousand, seventy-one".