1378109561 has 4 divisors (see below), whose sum is σ = 1438027392. Its totient is φ = 1318191732.

The previous prime is 1378109543. The next prime is 1378109569. The reversal of 1378109561 is 1659018731.

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 1378109561 - 2¹⁸ = 1377847417 is a prime.

It is a super-2 number, since 2×1378109561² = 3798371924239225442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1378109569) 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, 29958881 + ... + 29958926.

It is an arithmetic number, because the mean of its divisors is an integer number (359506848).

Almost surely, 2^1378109561 is an apocalyptic number.

It is an amenable number.

1378109561 is a deficient number, since it is larger than the sum of its proper divisors (59917831).

1378109561 is an equidigital number, since it uses as much as digits as its factorization.

1378109561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59917830.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 1378109561 is about 37122.8980684429. The cubic root of 1378109561 is about 1112.8276689314.

The spelling of 1378109561 in words is "one billion, three hundred seventy-eight million, one hundred nine thousand, five hundred sixty-one".