7751921 has 2 divisors, whose sum is σ = 7751922. Its totient is φ = 7751920.

The previous prime is 7751839. The next prime is 7751923. The reversal of 7751921 is 1291577.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7639696 + 112225 = 2764^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 7751921 - 2¹⁴ = 7735537 is a prime.

It is a super-4 number, since 4×7751921⁴ (a number of 29 digits) contains 4444 as substring.

Together with 7751923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (7751923) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3875960 + 3875961.

It is an arithmetic number, because the mean of its divisors is an integer number (3875961).

Almost surely, 2^7751921 is an apocalyptic number.

It is an amenable number.

7751921 is a deficient number, since it is larger than the sum of its proper divisors (1).

7751921 is an equidigital number, since it uses as much as digits as its factorization.

7751921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4410, while the sum is 32.

The square root of 7751921 is about 2784.2271818226. The cubic root of 7751921 is about 197.9109299070.

Adding to 7751921 its sum of digits (32), we get a triangular number (7751953 = T₃₉₃₇).

The spelling of 7751921 in words is "seven million, seven hundred fifty-one thousand, nine hundred twenty-one".