6401556461 has 2 divisors, whose sum is σ = 6401556462. Its totient is φ = 6401556460.

The previous prime is 6401556449. The next prime is 6401556481. The reversal of 6401556461 is 1646551046.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5960766436 + 440790025 = 77206^2 + 20995^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6401556461 is a prime.

It is a super-3 number, since 3×6401556461³ (a number of 30 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6401556481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3200778230 + 3200778231.

It is an arithmetic number, because the mean of its divisors is an integer number (3200778231).

Almost surely, 2^6401556461 is an apocalyptic number.

It is an amenable number.

6401556461 is a deficient number, since it is larger than the sum of its proper divisors (1).

6401556461 is an equidigital number, since it uses as much as digits as its factorization.

6401556461 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86400, while the sum is 38.

The square root of 6401556461 is about 80009.7272898739. The cubic root of 6401556461 is about 1856.7860306622.

The spelling of 6401556461 in words is "six billion, four hundred one million, five hundred fifty-six thousand, four hundred sixty-one".