21629399 has 8 divisors (see below), whose sum is σ = 23710080. Its totient is φ = 19567800.

The previous prime is 21629393. The next prime is 21629401. The reversal of 21629399 is 99392612.

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 21629399 - 2⁸ = 21629143 is a prime.

It is a super-2 number, since 2×21629399² = 935661802202402, 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 (21629393) 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, 2339 + ... + 6980.

It is an arithmetic number, because the mean of its divisors is an integer number (2963760).

Almost surely, 2^21629399 is an apocalyptic number.

21629399 is a deficient number, since it is larger than the sum of its proper divisors (2080681).

21629399 is a wasteful number, since it uses less digits than its factorization.

21629399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9541.

The product of its digits is 52488, while the sum is 41.

The square root of 21629399 is about 4650.7417687934. The cubic root of 21629399 is about 278.6216228015.

The spelling of 21629399 in words is "twenty-one million, six hundred twenty-nine thousand, three hundred ninety-nine".