21370019 has 4 divisors (see below), whose sum is σ = 23312760. Its totient is φ = 19427280.

The previous prime is 21370009. The next prime is 21370021. The reversal of 21370019 is 91007312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21370019 - 2²⁴ = 4592803 is a prime.

It is a super-2 number, since 2×21370019² = 913355424120722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21369976 and 21370003.

It is not an unprimeable number, because it can be changed into a prime (21370009) 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, 971354 + ... + 971375.

It is an arithmetic number, because the mean of its divisors is an integer number (5828190).

Almost surely, 2^21370019 is an apocalyptic number.

21370019 is a deficient number, since it is larger than the sum of its proper divisors (1942741).

21370019 is a wasteful number, since it uses less digits than its factorization.

21370019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1942740.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 21370019 is about 4622.7717875751. The cubic root of 21370019 is about 277.5033963278.

The spelling of 21370019 in words is "twenty-one million, three hundred seventy thousand, nineteen".