3731865921 has 27 divisors (see below), whose sum is σ = 6272706531. Its totient is φ = 2131761744.

The previous prime is 3731865883. The next prime is 3731865931. The reversal of 3731865921 is 1295681373.

The square root of 3731865921 is 61089.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3236358321 + 495507600 = 56889^2 + 22260^2 .

It is not a de Polignac number, because 3731865921 - 2¹³ = 3731857729 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3731865931) 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 26 ways as a sum of consecutive naturals, for example, 1281415 + ... + 1284323.

Almost surely, 2^3731865921 is an apocalyptic number.

3731865921 is the 61089-th square number.

3731865921 is the 30545-th centered octagonal number.

It is an amenable number.

3731865921 is a deficient number, since it is larger than the sum of its proper divisors (2540840610).

3731865921 is an frugal number, since it uses more digits than its factorization.

3731865921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5838 (or 2919 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The cubic root of 3731865921 is about 1551.1079031565.

The spelling of 3731865921 in words is "three billion, seven hundred thirty-one million, eight hundred sixty-five thousand, nine hundred twenty-one".