21479999 has 16 divisors (see below), whose sum is σ = 23265792. Its totient is φ = 19782048.

The previous prime is 21479963. The next prime is 21480001. The reversal of 21479999 is 99997412.

21479999 = 332² + 333² + ... + 465².

It is a cyclic number.

It is not a de Polignac number, because 21479999 - 2⁸ = 21479743 is a prime.

It is a super-2 number, since 2×21479999² = 922780714080002, which contains 22 as substring.

It is a Duffinian number.

21479999 is a modest number, since divided by 9999 gives 2147 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21472999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81542 + ... + 81804.

It is an arithmetic number, because the mean of its divisors is an integer number (1454112).

Almost surely, 2^21479999 is an apocalyptic number.

21479999 is a deficient number, since it is larger than the sum of its proper divisors (1785793).

21479999 is a wasteful number, since it uses less digits than its factorization.

21479999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406.

The product of its digits is 367416, while the sum is 50.

The square root of 21479999 is about 4634.6519826196. The cubic root of 21479999 is about 277.9786355923.

The spelling of 21479999 in words is "twenty-one million, four hundred seventy-nine thousand, nine hundred ninety-nine".