64400551 has 2 divisors, whose sum is σ = 64400552. Its totient is φ = 64400550.

The previous prime is 64400543. The next prime is 64400587. The reversal of 64400551 is 15500446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64400551 - 2³ = 64400543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64401551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32200275 + 32200276.

It is an arithmetic number, because the mean of its divisors is an integer number (32200276).

Almost surely, 2^64400551 is an apocalyptic number.

64400551 is a deficient number, since it is larger than the sum of its proper divisors (1).

64400551 is an equidigital number, since it uses as much as digits as its factorization.

64400551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 64400551 is about 8024.9953894068. The cubic root of 64400551 is about 400.8327463806.

Adding to 64400551 its reverse (15500446), we get a palindrome (79900997).

The spelling of 64400551 in words is "sixty-four million, four hundred thousand, five hundred fifty-one".