21007019 has 8 divisors (see below), whose sum is σ = 24265008. Its totient is φ = 17973760.

The previous prime is 21007013. The next prime is 21007067. The reversal of 21007019 is 91070012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21007019 - 2²⁰ = 19958443 is a prime.

It is a super-2 number, since 2×21007019² = 882589694532722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21007013) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55982 + ... + 56355.

It is an arithmetic number, because the mean of its divisors is an integer number (3033126).

Almost surely, 2^21007019 is an apocalyptic number.

21007019 is a deficient number, since it is larger than the sum of its proper divisors (3257989).

21007019 is a wasteful number, since it uses less digits than its factorization.

21007019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112365.

The product of its (nonzero) digits is 126, while the sum is 20.

The square root of 21007019 is about 4583.3414666595. The cubic root of 21007019 is about 275.9231521329.

It can be divided in two parts, 2100 and 7019, that added together give a palindrome (9119).

The spelling of 21007019 in words is "twenty-one million, seven thousand, nineteen".