21021020019 has 64 divisors (see below), whose sum is σ = 32092569600. Its totient is φ = 13595021856.

The previous prime is 21021019997. The next prime is 21021020057. The reversal of 21021020019 is 91002012012.

It is not a de Polignac number, because 21021020019 - 2⁷ = 21021019891 is a prime.

It is a super-2 number, since 2×21021020019² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21021019983 and 21021020010.

It is not an unprimeable number, because it can be changed into a prime (21021020089) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 35810644 + ... + 35811230.

It is an arithmetic number, because the mean of its divisors is an integer number (501446400).

Almost surely, 2^21021020019 is an apocalyptic number.

21021020019 is a deficient number, since it is larger than the sum of its proper divisors (11071549581).

21021020019 is a wasteful number, since it uses less digits than its factorization.

21021020019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 941 (or 935 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

It can be divided in two parts, 2102 and 1020019, that added together give a square (1022121 = 1011²).

The spelling of 21021020019 in words is "twenty-one billion, twenty-one million, twenty thousand, nineteen".