21011851207 has 2 divisors, whose sum is σ = 21011851208. Its totient is φ = 21011851206.

The previous prime is 21011851141. The next prime is 21011851277. The reversal of 21011851207 is 70215811012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011851207 is a prime.

It is a super-2 number, since 2×21011851207² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011851277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505925603 + 10505925604.

It is an arithmetic number, because the mean of its divisors is an integer number (10505925604).

Almost surely, 2^21011851207 is an apocalyptic number.

21011851207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011851207 is an equidigital number, since it uses as much as digits as its factorization.

21011851207 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1120, while the sum is 28.

The spelling of 21011851207 in words is "twenty-one billion, eleven million, eight hundred fifty-one thousand, two hundred seven".