3967761221776 has 135 divisors (see below), whose sum is σ = 8979603456313. Its totient is φ = 1696800540160.

The previous prime is 3967761221773. The next prime is 3967761221803. The reversal of 3967761221776 is 6771221677693.

It is a happy number.

The square root of 3967761221776 is 1991924.

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., 3089087456400 + 878673765376 = 1757580^2 + 937376^2 .

It is a super-2 number, since 2×3967761221776² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3967761221771) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1489957821 + ... + 1489960483.

Almost surely, 2^{3967761221776} is an apocalyptic number.

3967761221776 is the 1991924-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3967761221776

3967761221776 is an abundant number, since it is smaller than the sum of its proper divisors (5011842234537).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3967761221776 is an equidigital number, since it uses as much as digits as its factorization.

3967761221776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5390 (or 2693 counting only the distinct ones).

The product of its digits is 56010528, while the sum is 64.

Multiplying 3967761221776 by its sum of digits (64), we get a square (253936718193664 = 15935392²).

The spelling of 3967761221776 in words is "three trillion, nine hundred sixty-seven billion, seven hundred sixty-one million, two hundred twenty-one thousand, seven hundred seventy-six".