123621661551 has 8 divisors (see below), whose sum is σ = 164850746800. Its totient is φ = 82403508672.

The previous prime is 123621661489. The next prime is 123621661567. The reversal of 123621661551 is 155166126321.

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

It is not a de Polignac number, because 123621661551 - 2⁹ = 123621661039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123621661591) 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, 2706670 + ... + 2751963.

It is an arithmetic number, because the mean of its divisors is an integer number (20606343350).

Almost surely, 2^123621661551 is an apocalyptic number.

123621661551 is a deficient number, since it is larger than the sum of its proper divisors (41229085249).

123621661551 is an equidigital number, since it uses as much as digits as its factorization.

123621661551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5466185.

The product of its digits is 64800, while the sum is 39.

Adding to 123621661551 its reverse (155166126321), we get a palindrome (278787787872).

The spelling of 123621661551 in words is "one hundred twenty-three billion, six hundred twenty-one million, six hundred sixty-one thousand, five hundred fifty-one".