21019019615 has 16 divisors (see below), whose sum is σ = 28186927776. Its totient is φ = 14913715200.

The previous prime is 21019019603. The next prime is 21019019633. The reversal of 21019019615 is 51691091012.

It is not a de Polignac number, because 21019019615 - 2¹² = 21019015519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4658282 + ... + 4662791.

It is an arithmetic number, because the mean of its divisors is an integer number (1761682986).

Almost surely, 2^21019019615 is an apocalyptic number.

21019019615 is a deficient number, since it is larger than the sum of its proper divisors (7167908161).

21019019615 is a wasteful number, since it uses less digits than its factorization.

21019019615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9321130.

The product of its (nonzero) digits is 4860, while the sum is 35.

The spelling of 21019019615 in words is "twenty-one billion, nineteen million, nineteen thousand, six hundred fifteen".