1381021871 has 4 divisors (see below), whose sum is σ = 1388252544. Its totient is φ = 1373791200.

The previous prime is 1381021861. The next prime is 1381021879. The reversal of 1381021871 is 1781201831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1781201831 = 10837 ⋅164363.

It is a cyclic number.

It is not a de Polignac number, because 1381021871 - 2¹⁸ = 1380759727 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 (1381021879) 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, 3615050 + ... + 3615431.

It is an arithmetic number, because the mean of its divisors is an integer number (347063136).

Almost surely, 2^1381021871 is an apocalyptic number.

1381021871 is a deficient number, since it is larger than the sum of its proper divisors (7230673).

1381021871 is an equidigital number, since it uses as much as digits as its factorization.

1381021871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7230672.

The product of its (nonzero) digits is 2688, while the sum is 32.

The square root of 1381021871 is about 37162.1026181243. The cubic root of 1381021871 is about 1113.6110171154.

The spelling of 1381021871 in words is "one billion, three hundred eighty-one million, twenty-one thousand, eight hundred seventy-one".