640346121 has 8 divisors (see below), whose sum is σ = 948660960. Its totient is φ = 426897396.

The previous prime is 640346117. The next prime is 640346141. The reversal of 640346121 is 121643046.

640346121 is a `hidden beast` number, since 6 + 40 + 3 + 4 + 612 + 1 = 666.

It is not a de Polignac number, because 640346121 - 2² = 640346117 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 23716523 = 640346121 / (6 + 4 + 0 + 3 + 4 + 6 + 1 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (640346141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11858235 + ... + 11858288.

It is an arithmetic number, because the mean of its divisors is an integer number (118582620).

Almost surely, 2^640346121 is an apocalyptic number.

It is an amenable number.

640346121 is a deficient number, since it is larger than the sum of its proper divisors (308314839).

640346121 is a wasteful number, since it uses less digits than its factorization.

640346121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23716532 (or 23716526 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 640346121 is about 25305.0611736071. The cubic root of 640346121 is about 861.9292011591.

Adding to 640346121 its reverse (121643046), we get a palindrome (761989167).

The spelling of 640346121 in words is "six hundred forty million, three hundred forty-six thousand, one hundred twenty-one".