661624618397 has 16 divisors (see below), whose sum is σ = 676673585280. Its totient is φ = 646707604032.

The previous prime is 661624618393. The next prime is 661624618429. The reversal of 661624618397 is 793816426166.

It is a cyclic number.

It is not a de Polignac number, because 661624618397 - 2² = 661624618393 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661624618393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19660928 + ... + 19694550.

It is an arithmetic number, because the mean of its divisors is an integer number (42292099080).

Almost surely, 2^661624618397 is an apocalyptic number.

It is an amenable number.

661624618397 is a deficient number, since it is larger than the sum of its proper divisors (15048966883).

661624618397 is a wasteful number, since it uses less digits than its factorization.

661624618397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35572.

The product of its digits is 15676416, while the sum is 59.

The spelling of 661624618397 in words is "six hundred sixty-one billion, six hundred twenty-four million, six hundred eighteen thousand, three hundred ninety-seven".