661287218158 has 8 divisors (see below), whose sum is σ = 1133635231152. Its totient is φ = 283408807776.

The previous prime is 661287218069. The next prime is 661287218177. The reversal of 661287218158 is 851812782166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 661287218099 and 661287218108.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23617400635 + ... + 23617400662.

It is an arithmetic number, because the mean of its divisors is an integer number (141704403894).

Almost surely, 2^661287218158 is an apocalyptic number.

661287218158 is a deficient number, since it is larger than the sum of its proper divisors (472348012994).

661287218158 is a wasteful number, since it uses less digits than its factorization.

661287218158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47234801306.

The product of its digits is 2580480, while the sum is 55.

The spelling of 661287218158 in words is "six hundred sixty-one billion, two hundred eighty-seven million, two hundred eighteen thousand, one hundred fifty-eight".