8400756421 has 2 divisors, whose sum is σ = 8400756422. Its totient is φ = 8400756420.

The previous prime is 8400756409. The next prime is 8400756443. The reversal of 8400756421 is 1246570048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5795776900 + 2604979521 = 76130^2 + 51039^2 .

It is a cyclic number.

It is not a de Polignac number, because 8400756421 - 2⁵ = 8400756389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8400756461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4200378210 + 4200378211.

It is an arithmetic number, because the mean of its divisors is an integer number (4200378211).

Almost surely, 2^8400756421 is an apocalyptic number.

It is an amenable number.

8400756421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8400756421 is an equidigital number, since it uses as much as digits as its factorization.

8400756421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 53760, while the sum is 37.

The square root of 8400756421 is about 91655.6404210892. The cubic root of 8400756421 is about 2032.8537295402.

The spelling of 8400756421 in words is "eight billion, four hundred million, seven hundred fifty-six thousand, four hundred twenty-one".