78421029621 has 16 divisors (see below), whose sum is σ = 114088177728. Its totient is φ = 47519052800.

The previous prime is 78421029569. The next prime is 78421029641. The reversal of 78421029621 is 12692012487.

It is a cyclic number.

It is not a de Polignac number, because 78421029621 - 2³¹ = 76273545973 is a prime.

It is a super-2 number, since 2×78421029621² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78421029641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38826 + ... + 397931.

It is an arithmetic number, because the mean of its divisors is an integer number (7130511108).

Almost surely, 2^78421029621 is an apocalyptic number.

It is an amenable number.

78421029621 is a deficient number, since it is larger than the sum of its proper divisors (35667148107).

78421029621 is a wasteful number, since it uses less digits than its factorization.

78421029621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442212.

The product of its (nonzero) digits is 96768, while the sum is 42.

The spelling of 78421029621 in words is "seventy-eight billion, four hundred twenty-one million, twenty-nine thousand, six hundred twenty-one".