3771221621 has 2 divisors, whose sum is σ = 3771221622. Its totient is φ = 3771221620.

The previous prime is 3771221617. The next prime is 3771221677. The reversal of 3771221621 is 1261221773.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3734920996 + 36300625 = 61114^2 + 6025^2 .

It is a cyclic number.

It is not a de Polignac number, because 3771221621 - 2² = 3771221617 is a prime.

It is a super-2 number, since 2×3771221621² = 28444225029395735282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3771221681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1885610810 + 1885610811.

It is an arithmetic number, because the mean of its divisors is an integer number (1885610811).

Almost surely, 2^3771221621 is an apocalyptic number.

It is an amenable number.

3771221621 is a deficient number, since it is larger than the sum of its proper divisors (1).

3771221621 is an equidigital number, since it uses as much as digits as its factorization.

3771221621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 32.

The square root of 3771221621 is about 61410.2729272554. The cubic root of 3771221621 is about 1556.5414312988.

The spelling of 3771221621 in words is "three billion, seven hundred seventy-one million, two hundred twenty-one thousand, six hundred twenty-one".