42021220061 has 2 divisors, whose sum is σ = 42021220062. Its totient is φ = 42021220060.

The previous prime is 42021220057. The next prime is 42021220091. The reversal of 42021220061 is 16002212024.

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., 32867514436 + 9153705625 = 181294^2 + 95675^2 .

It is a cyclic number.

It is not a de Polignac number, because 42021220061 - 2² = 42021220057 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42021220091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21010610030 + 21010610031.

It is an arithmetic number, because the mean of its divisors is an integer number (21010610031).

Almost surely, 2^42021220061 is an apocalyptic number.

It is an amenable number.

42021220061 is a deficient number, since it is larger than the sum of its proper divisors (1).

42021220061 is an equidigital number, since it uses as much as digits as its factorization.

42021220061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 42021220061 its reverse (16002212024), we get a palindrome (58023432085).

The spelling of 42021220061 in words is "forty-two billion, twenty-one million, two hundred twenty thousand, sixty-one".