640711155121 has 4 divisors (see below), whose sum is σ = 640713928192. Its totient is φ = 640708382052.

The previous prime is 640711155083. The next prime is 640711155137. The reversal of 640711155121 is 121551117046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 121551117046 = 2 ⋅60775558523.

It is a cyclic number.

It is not a de Polignac number, because 640711155121 - 2¹⁷ = 640711024049 is a prime.

It is a super-2 number, since 2×640711155121² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640711158121) 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, 1004961 + ... + 1513726.

It is an arithmetic number, because the mean of its divisors is an integer number (160178482048).

Almost surely, 2^640711155121 is an apocalyptic number.

It is an amenable number.

640711155121 is a deficient number, since it is larger than the sum of its proper divisors (2773071).

640711155121 is a wasteful number, since it uses less digits than its factorization.

640711155121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2773070.

The product of its (nonzero) digits is 8400, while the sum is 34.

The spelling of 640711155121 in words is "six hundred forty billion, seven hundred eleven million, one hundred fifty-five thousand, one hundred twenty-one".