7405761721 has 2 divisors, whose sum is σ = 7405761722. Its totient is φ = 7405761720.

The previous prime is 7405761667. The next prime is 7405761739. The reversal of 7405761721 is 1271675047.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7385511721 + 20250000 = 85939^2 + 4500^2 .

It is a cyclic number.

It is not a de Polignac number, because 7405761721 - 2¹³ = 7405753529 is a prime.

It is not a weakly prime, because it can be changed into another prime (7405765721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3702880860 + 3702880861.

It is an arithmetic number, because the mean of its divisors is an integer number (3702880861).

Almost surely, 2^7405761721 is an apocalyptic number.

It is an amenable number.

7405761721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7405761721 is an equidigital number, since it uses as much as digits as its factorization.

7405761721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82320, while the sum is 40.

The square root of 7405761721 is about 86056.7354772420. The cubic root of 7405761721 is about 1949.2007876291.

The spelling of 7405761721 in words is "seven billion, four hundred five million, seven hundred sixty-one thousand, seven hundred twenty-one".