378315721 has 6 divisors (see below), whose sum is σ = 440081610. Its totient is φ = 324270576.

The previous prime is 378315689. The next prime is 378315731. The reversal of 378315721 is 127513873.

It can be written as a sum of positive squares in only one way, i.e., 210975625 + 167340096 = 14525^2 + 12936^2 .

It is not a de Polignac number, because 378315721 - 2⁵ = 378315689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (378315731) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3860316 + ... + 3860413.

It is an arithmetic number, because the mean of its divisors is an integer number (73346935).

Almost surely, 2^378315721 is an apocalyptic number.

It is an amenable number.

378315721 is a deficient number, since it is larger than the sum of its proper divisors (61765889).

378315721 is an equidigital number, since it uses as much as digits as its factorization.

378315721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7720743 (or 7720736 counting only the distinct ones).

The product of its digits is 35280, while the sum is 37.

The square root of 378315721 is about 19450.3398684959. The cubic root of 378315721 is about 723.2439281335.

The spelling of 378315721 in words is "three hundred seventy-eight million, three hundred fifteen thousand, seven hundred twenty-one".