634400551 has 4 divisors (see below), whose sum is σ = 634476312. Its totient is φ = 634324792.

The previous prime is 634400531. The next prime is 634400561. The reversal of 634400551 is 155004436.

634400551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 634400551 - 2¹³ = 634392359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634400521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23500 + ... + 42673.

It is an arithmetic number, because the mean of its divisors is an integer number (158619078).

Almost surely, 2^634400551 is an apocalyptic number.

634400551 is a deficient number, since it is larger than the sum of its proper divisors (75761).

634400551 is an equidigital number, since it uses as much as digits as its factorization.

634400551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75760.

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 634400551 is about 25187.3093243403. The cubic root of 634400551 is about 859.2532507299.

Adding to 634400551 its reverse (155004436), we get a palindrome (789404987).

The spelling of 634400551 in words is "six hundred thirty-four million, four hundred thousand, five hundred fifty-one".