1377265621 has 4 divisors (see below), whose sum is σ = 1380253644. Its totient is φ = 1374277600.

The previous prime is 1377265609. The next prime is 1377265639. The reversal of 1377265621 is 1265627731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1265627731 = 31 ⋅40826701.

It can be written as a sum of positive squares in 2 ways, for example, as 165251025 + 1212014596 = 12855^2 + 34814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1377265621 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 (1377265661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1493320 + ... + 1494241.

It is an arithmetic number, because the mean of its divisors is an integer number (345063411).

Almost surely, 2^1377265621 is an apocalyptic number.

It is an amenable number.

1377265621 is a deficient number, since it is larger than the sum of its proper divisors (2988023).

1377265621 is an equidigital number, since it uses as much as digits as its factorization.

1377265621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2988022.

The product of its digits is 105840, while the sum is 40.

The square root of 1377265621 is about 37111.5294888260. The cubic root of 1377265621 is about 1112.6004611715.

The spelling of 1377265621 in words is "one billion, three hundred seventy-seven million, two hundred sixty-five thousand, six hundred twenty-one".