21020991631603 has 2 divisors, whose sum is σ = 21020991631604. Its totient is φ = 21020991631602.

The previous prime is 21020991631589. The next prime is 21020991631621. The reversal of 21020991631603 is 30613619902012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21020991631603 - 2²¹ = 21020989534451 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21020991631603.

It is not a weakly prime, because it can be changed into another prime (21020991631103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510495815801 + 10510495815802.

It is an arithmetic number, because the mean of its divisors is an integer number (10510495815802).

Almost surely, 2^{21020991631603} is an apocalyptic number.

21020991631603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020991631603 is an equidigital number, since it uses as much as digits as its factorization.

21020991631603 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 43.

The spelling of 21020991631603 in words is "twenty-one trillion, twenty billion, nine hundred ninety-one million, six hundred thirty-one thousand, six hundred three".