21429779 has 8 divisors (see below), whose sum is σ = 24530688. Its totient is φ = 18338760.

The previous prime is 21429763. The next prime is 21429799. The reversal of 21429779 is 97792412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21429779 - 2⁴ = 21429763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21429719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2984 + ... + 7194.

It is an arithmetic number, because the mean of its divisors is an integer number (3066336).

Almost surely, 2^21429779 is an apocalyptic number.

21429779 is a deficient number, since it is larger than the sum of its proper divisors (3100909).

21429779 is an equidigital number, since it uses as much as digits as its factorization.

21429779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4945.

The product of its digits is 63504, while the sum is 41.

The square root of 21429779 is about 4629.2309296470. The cubic root of 21429779 is about 277.7618295496.

The spelling of 21429779 in words is "twenty-one million, four hundred twenty-nine thousand, seven hundred seventy-nine".