38784969721 has 9 divisors (see below), whose sum is σ = 40174415983. Its totient is φ = 37442042680.

The previous prime is 38784969661. The next prime is 38784969731. The reversal of 38784969721 is 12796948783.

The square root of 38784969721 is 196939.

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., 20337897321 + 18447072400 = 142611^2 + 135820^2 .

It is not a de Polignac number, because 38784969721 - 2¹¹ = 38784967673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (38784969731) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5707836 + ... + 5714626.

Almost surely, 2^38784969721 is an apocalyptic number.

38784969721 is the 196939-th square number.

38784969721 is the 98470-th centered octagonal number.

It is an amenable number.

38784969721 is a deficient number, since it is larger than the sum of its proper divisors (1389446262).

38784969721 is an frugal number, since it uses more digits than its factorization.

38784969721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13640 (or 6820 counting only the distinct ones).

The product of its digits is 36578304, while the sum is 64.

Multiplying 38784969721 by its sum of digits (64), we get a square (2482238062144 = 1575512²).

The spelling of 38784969721 in words is "thirty-eight billion, seven hundred eighty-four million, nine hundred sixty-nine thousand, seven hundred twenty-one".