121265784640 has 448 divisors, whose sum is σ = 389185026048. Its totient is φ = 34757222400.

The previous prime is 121265784589. The next prime is 121265784671. The reversal of 121265784640 is 46487562121.

It is a tau number, because it is divible by the number of its divisors (448).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 111150495 + ... + 111151585.

It is an arithmetic number, because the mean of its divisors is an integer number (868716576).

Almost surely, 2^121265784640 is an apocalyptic number.

121265784640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121265784640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (194592513024).

121265784640 is an abundant number, since it is smaller than the sum of its proper divisors (267919241408).

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

121265784640 is a wasteful number, since it uses less digits than its factorization.

121265784640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486 (or 1476 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 46.

The spelling of 121265784640 in words is "one hundred twenty-one billion, two hundred sixty-five million, seven hundred eighty-four thousand, six hundred forty".