21019019613 has 4 divisors (see below), whose sum is σ = 28025359488. Its totient is φ = 14012679740.

The previous prime is 21019019603. The next prime is 21019019633. The reversal of 21019019613 is 31691091012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21019019613 - 2¹² = 21019015517 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21019019603) 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, 3503169933 + ... + 3503169938.

It is an arithmetic number, because the mean of its divisors is an integer number (7006339872).

Almost surely, 2^21019019613 is an apocalyptic number.

It is an amenable number.

21019019613 is a deficient number, since it is larger than the sum of its proper divisors (7006339875).

21019019613 is an equidigital number, since it uses as much as digits as its factorization.

21019019613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7006339874.

The product of its (nonzero) digits is 2916, while the sum is 33.

The spelling of 21019019613 in words is "twenty-one billion, nineteen million, nineteen thousand, six hundred thirteen".