21019017101 has 2 divisors, whose sum is σ = 21019017102. Its totient is φ = 21019017100.

The previous prime is 21019017067. The next prime is 21019017109. The reversal of 21019017101 is 10171091012.

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., 20843851876 + 175165225 = 144374^2 + 13235^2 .

It is a cyclic number.

It is not a de Polignac number, because 21019017101 - 2⁶ = 21019017037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21019017109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10509508550 + 10509508551.

It is an arithmetic number, because the mean of its divisors is an integer number (10509508551).

Almost surely, 2^21019017101 is an apocalyptic number.

It is an amenable number.

21019017101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21019017101 is an equidigital number, since it uses as much as digits as its factorization.

21019017101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 126, while the sum is 23.

The spelling of 21019017101 in words is "twenty-one billion, nineteen million, seventeen thousand, one hundred one".