42531610621 has 2 divisors, whose sum is σ = 42531610622. Its totient is φ = 42531610620.

The previous prime is 42531610613. The next prime is 42531610657. The reversal of 42531610621 is 12601613524.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35137502500 + 7394108121 = 187450^2 + 85989^2 .

It is a cyclic number.

It is not a de Polignac number, because 42531610621 - 2³ = 42531610613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42531610421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21265805310 + 21265805311.

It is an arithmetic number, because the mean of its divisors is an integer number (21265805311).

Almost surely, 2^42531610621 is an apocalyptic number.

It is an amenable number.

42531610621 is a deficient number, since it is larger than the sum of its proper divisors (1).

42531610621 is an equidigital number, since it uses as much as digits as its factorization.

42531610621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 31.

The spelling of 42531610621 in words is "forty-two billion, five hundred thirty-one million, six hundred ten thousand, six hundred twenty-one".