640000615551 has 32 divisors (see below), whose sum is σ = 953815516416. Its totient is φ = 378339168000.

The previous prime is 640000615549. The next prime is 640000615571. The reversal of 640000615551 is 155516000046.

It is not a de Polignac number, because 640000615551 - 2¹ = 640000615549 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640000615571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6732685 + ... + 6827081.

It is an arithmetic number, because the mean of its divisors is an integer number (29806734888).

Almost surely, 2^640000615551 is an apocalyptic number.

640000615551 is a deficient number, since it is larger than the sum of its proper divisors (313814900865).

640000615551 is a wasteful number, since it uses less digits than its factorization.

640000615551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99463.

The product of its (nonzero) digits is 18000, while the sum is 33.

Adding to 640000615551 its reverse (155516000046), we get a palindrome (795516615597).

The spelling of 640000615551 in words is "six hundred forty billion, six hundred fifteen thousand, five hundred fifty-one".