642621632121 has 24 divisors (see below), whose sum is σ = 1060992354240. Its totient is φ = 367158138336.

The previous prime is 642621632087. The next prime is 642621632129. The reversal of 642621632121 is 121236126246.

642621632121 is a `hidden beast` number, since 6 + 4 + 2 + 6 + 2 + 1 + 632 + 12 + 1 = 666.

It is not a de Polignac number, because 642621632121 - 2¹⁴ = 642621615737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (642621632129) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 321106 + ... + 1178283.

It is an arithmetic number, because the mean of its divisors is an integer number (44208014760).

Almost surely, 2^642621632121 is an apocalyptic number.

It is an amenable number.

642621632121 is a deficient number, since it is larger than the sum of its proper divisors (418370722119).

642621632121 is a wasteful number, since it uses less digits than its factorization.

642621632121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1506205 (or 1506202 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

Adding to 642621632121 its reverse (121236126246), we get a palindrome (763857758367).

The spelling of 642621632121 in words is "six hundred forty-two billion, six hundred twenty-one million, six hundred thirty-two thousand, one hundred twenty-one".