21436869 has 4 divisors (see below), whose sum is σ = 28582496. Its totient is φ = 14291244.

The previous prime is 21436853. The next prime is 21436871. The reversal of 21436869 is 96863412.

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 not a de Polignac number, because 21436869 - 2⁴ = 21436853 is a prime.

It is a super-2 number, since 2×21436869² = 919078705046322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21436169) 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, 3572809 + ... + 3572814.

It is an arithmetic number, because the mean of its divisors is an integer number (7145624).

Almost surely, 2^21436869 is an apocalyptic number.

It is an amenable number.

21436869 is a deficient number, since it is larger than the sum of its proper divisors (7145627).

21436869 is an equidigital number, since it uses as much as digits as its factorization.

21436869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7145626.

The product of its digits is 62208, while the sum is 39.

The square root of 21436869 is about 4629.9966522666. The cubic root of 21436869 is about 277.7924584893.

The spelling of 21436869 in words is "twenty-one million, four hundred thirty-six thousand, eight hundred sixty-nine".