387691515628221 has 64 divisors (see below), whose sum is σ = 626402996142080. Its totient is φ = 208565219450880.

The previous prime is 387691515628201. The next prime is 387691515628231. The reversal of 387691515628221 is 122826515196783.

It is a happy number.

It is not a de Polignac number, because 387691515628221 - 2⁵ = 387691515628189 is a prime.

It is a super-2 number, since 2×387691515628221² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (387691515628201) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 156031410 + ... + 158496636.

It is an arithmetic number, because the mean of its divisors is an integer number (9787546814720).

Almost surely, 2^{387691515628221} is an apocalyptic number.

387691515628221 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

387691515628221 is a deficient number, since it is larger than the sum of its proper divisors (238711480513859).

387691515628221 is a wasteful number, since it uses less digits than its factorization.

387691515628221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2471834.

The product of its digits is 87091200, while the sum is 66.

The spelling of 387691515628221 in words is "three hundred eighty-seven trillion, six hundred ninety-one billion, five hundred fifteen million, six hundred twenty-eight thousand, two hundred twenty-one".