42021094721 has 2 divisors, whose sum is σ = 42021094722. Its totient is φ = 42021094720.

The previous prime is 42021094681. The next prime is 42021094727. The reversal of 42021094721 is 12749012024.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39109413121 + 2911681600 = 197761^2 + 53960^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42021094721 is a prime.

It is not a weakly prime, because it can be changed into another prime (42021094727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21010547360 + 21010547361.

It is an arithmetic number, because the mean of its divisors is an integer number (21010547361).

Almost surely, 2^42021094721 is an apocalyptic number.

It is an amenable number.

42021094721 is a deficient number, since it is larger than the sum of its proper divisors (1).

42021094721 is an equidigital number, since it uses as much as digits as its factorization.

42021094721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 32.

The spelling of 42021094721 in words is "forty-two billion, twenty-one million, ninety-four thousand, seven hundred twenty-one".