42402640421 has 2 divisors, whose sum is σ = 42402640422. Its totient is φ = 42402640420.

The previous prime is 42402640409. The next prime is 42402640451. The reversal of 42402640421 is 12404620424.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41988517921 + 414122500 = 204911^2 + 20350^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42402640421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42402640451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21201320210 + 21201320211.

It is an arithmetic number, because the mean of its divisors is an integer number (21201320211).

Almost surely, 2^42402640421 is an apocalyptic number.

It is an amenable number.

42402640421 is a deficient number, since it is larger than the sum of its proper divisors (1).

42402640421 is an equidigital number, since it uses as much as digits as its factorization.

42402640421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12288, while the sum is 29.

The spelling of 42402640421 in words is "forty-two billion, four hundred two million, six hundred forty thousand, four hundred twenty-one".