21070019 has 4 divisors (see below), whose sum is σ = 21079344. Its totient is φ = 21060696.

The previous prime is 21070013. The next prime is 21070033. The reversal of 21070019 is 91007012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21070019 is a prime.

It is a super-2 number, since 2×21070019² = 887891401320722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21070013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1109 + ... + 6585.

It is an arithmetic number, because the mean of its divisors is an integer number (5269836).

Almost surely, 2^21070019 is an apocalyptic number.

21070019 is a deficient number, since it is larger than the sum of its proper divisors (9325).

21070019 is an equidigital number, since it uses as much as digits as its factorization.

21070019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9324.

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

The square root of 21070019 is about 4590.2090366344. The cubic root of 21070019 is about 276.1987078115.

The spelling of 21070019 in words is "twenty-one million, seventy thousand, nineteen".