21021121007 has 2 divisors, whose sum is σ = 21021121008. Its totient is φ = 21021121006.

The previous prime is 21021120941. The next prime is 21021121081. The reversal of 21021121007 is 70012112012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21021121007 - 2⁸ = 21021120751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021121307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510560503 + 10510560504.

It is an arithmetic number, because the mean of its divisors is an integer number (10510560504).

Almost surely, 2^21021121007 is an apocalyptic number.

21021121007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021121007 is an equidigital number, since it uses as much as digits as its factorization.

21021121007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 17.

Adding to 21021121007 its reverse (70012112012), we get a palindrome (91033233019).

The spelling of 21021121007 in words is "twenty-one billion, twenty-one million, one hundred twenty-one thousand, seven".