671501215621 has 16 divisors (see below), whose sum is σ = 718192790784. Its totient is φ = 626412776704.

The previous prime is 671501215549. The next prime is 671501215717. The reversal of 671501215621 is 126512105176.

671501215621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 671501215621 - 2¹⁵ = 671501182853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671501225621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1445716 + ... + 1852861.

It is an arithmetic number, because the mean of its divisors is an integer number (44887049424).

Almost surely, 2^671501215621 is an apocalyptic number.

It is an amenable number.

671501215621 is a deficient number, since it is larger than the sum of its proper divisors (46691575163).

671501215621 is a wasteful number, since it uses less digits than its factorization.

671501215621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3298820.

The product of its (nonzero) digits is 25200, while the sum is 37.

The spelling of 671501215621 in words is "six hundred seventy-one billion, five hundred one million, two hundred fifteen thousand, six hundred twenty-one".