121551955453518 has 16 divisors (see below), whose sum is σ = 244652343462480. Its totient is φ = 40259246391936.

The previous prime is 121551955453501. The next prime is 121551955453519. The reversal of 121551955453518 is 815354559155121.

It is a super-2 number, since 2×121551955453518² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121551955453519) 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, 64518022123 + ... + 64518024006.

It is an arithmetic number, because the mean of its divisors is an integer number (15290771466405).

Almost surely, 2^{121551955453518} is an apocalyptic number.

121551955453518 is an abundant number, since it is smaller than the sum of its proper divisors (123100388008962).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121551955453518 is a wasteful number, since it uses less digits than its factorization.

121551955453518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129036046291.

The product of its digits is 27000000, while the sum is 60.

The spelling of 121551955453518 in words is "one hundred twenty-one trillion, five hundred fifty-one billion, nine hundred fifty-five million, four hundred fifty-three thousand, five hundred eighteen".