21020210019971 has 2 divisors, whose sum is σ = 21020210019972. Its totient is φ = 21020210019970.

The previous prime is 21020210019953. The next prime is 21020210020057. The reversal of 21020210019971 is 17991001202012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21020210019971 - 2²² = 21020205825667 is a prime.

It is not a weakly prime, because it can be changed into another prime (21020210019901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510105009985 + 10510105009986.

It is an arithmetic number, because the mean of its divisors is an integer number (10510105009986).

Almost surely, 2^{21020210019971} is an apocalyptic number.

21020210019971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020210019971 is an equidigital number, since it uses as much as digits as its factorization.

21020210019971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 35.

The spelling of 21020210019971 in words is "twenty-one trillion, twenty billion, two hundred ten million, nineteen thousand, nine hundred seventy-one".