661206415 has 16 divisors (see below), whose sum is σ = 876650688. Its totient is φ = 476202496.

The previous prime is 661206407. The next prime is 661206431. The reversal of 661206415 is 514602166.

It is a cyclic number.

It is not a de Polignac number, because 661206415 - 2³ = 661206407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167152 + ... + 171061.

It is an arithmetic number, because the mean of its divisors is an integer number (54790668).

Almost surely, 2^661206415 is an apocalyptic number.

661206415 is a deficient number, since it is larger than the sum of its proper divisors (215444273).

661206415 is a wasteful number, since it uses less digits than its factorization.

661206415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338258.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 661206415 is about 25713.9342575188. The cubic root of 661206415 is about 871.1889390434.

The spelling of 661206415 in words is "six hundred sixty-one million, two hundred six thousand, four hundred fifteen".