4078187791621 has 8 divisors (see below), whose sum is σ = 4210415241984. Its totient is φ = 3946002404160.

The previous prime is 4078187791591. The next prime is 4078187791633. The reversal of 4078187791621 is 1261977818704.

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

It is a cyclic number.

It is not a de Polignac number, because 4078187791621 - 2³¹ = 4076040307973 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4078187791621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4078187791921) 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, 10318615 + ... + 10706548.

It is an arithmetic number, because the mean of its divisors is an integer number (526301905248).

Almost surely, 2^{4078187791621} is an apocalyptic number.

It is an amenable number.

4078187791621 is a deficient number, since it is larger than the sum of its proper divisors (132227450363).

4078187791621 is a wasteful number, since it uses less digits than its factorization.

4078187791621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21031451.

The product of its (nonzero) digits is 9483264, while the sum is 61.

The spelling of 4078187791621 in words is "four trillion, seventy-eight billion, one hundred eighty-seven million, seven hundred ninety-one thousand, six hundred twenty-one".