642370155642421 has 2 divisors, whose sum is σ = 642370155642422. Its totient is φ = 642370155642420.

The previous prime is 642370155642349. The next prime is 642370155642431. The reversal of 642370155642421 is 124246551073246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 523862329265521 + 118507826376900 = 22888039^2 + 10886130^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642370155642421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642370155642431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321185077821210 + 321185077821211.

It is an arithmetic number, because the mean of its divisors is an integer number (321185077821211).

Almost surely, 2^{642370155642421} is an apocalyptic number.

It is an amenable number.

642370155642421 is a deficient number, since it is larger than the sum of its proper divisors (1).

642370155642421 is an equidigital number, since it uses as much as digits as its factorization.

642370155642421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9676800, while the sum is 52.

The spelling of 642370155642421 in words is "six hundred forty-two trillion, three hundred seventy billion, one hundred fifty-five million, six hundred forty-two thousand, four hundred twenty-one".