861734379621 has 4 divisors (see below), whose sum is σ = 1148979172832. Its totient is φ = 574489586412.

The previous prime is 861734379607. The next prime is 861734379641. The reversal of 861734379621 is 126973437168.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 861734379621 - 2¹³ = 861734371429 is a prime.

It is a super-2 number, since 2×861734379621² (a number of 25 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 (861734379601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 143622396601 + ... + 143622396606.

It is an arithmetic number, because the mean of its divisors is an integer number (287244793208).

Almost surely, 2^861734379621 is an apocalyptic number.

It is an amenable number.

861734379621 is a deficient number, since it is larger than the sum of its proper divisors (287244793211).

861734379621 is a wasteful number, since it uses less digits than its factorization.

861734379621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287244793210.

The product of its digits is 9144576, while the sum is 57.

The spelling of 861734379621 in words is "eight hundred sixty-one billion, seven hundred thirty-four million, three hundred seventy-nine thousand, six hundred twenty-one".