21053619 has 24 divisors (see below), whose sum is σ = 31948800. Its totient is φ = 13342320.

The previous prime is 21053609. The next prime is 21053639. The reversal of 21053619 is 91635012.

It is not a de Polignac number, because 21053619 - 2⁷ = 21053491 is a prime.

It is a super-2 number, since 2×21053619² = 886509745994322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21053592 and 21053601.

It is not an unprimeable number, because it can be changed into a prime (21053609) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15822 + ... + 17100.

It is an arithmetic number, because the mean of its divisors is an integer number (1331200).

Almost surely, 2^21053619 is an apocalyptic number.

21053619 is a deficient number, since it is larger than the sum of its proper divisors (10895181).

21053619 is a wasteful number, since it uses less digits than its factorization.

21053619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1375 (or 1372 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21053619 is about 4588.4222778641. The cubic root of 21053619 is about 276.1270287977.

The spelling of 21053619 in words is "twenty-one million, fifty-three thousand, six hundred nineteen".