21477929 has 12 divisors (see below), whose sum is σ = 24500112. Its totient is φ = 18671400.

The previous prime is 21477913. The next prime is 21477959. The reversal of 21477929 is 92977412.

It is not a de Polignac number, because 21477929 - 2⁴ = 21477913 is a prime.

It is a super-2 number, since 2×21477929² = 922602868258082, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21477959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3974 + ... + 7664.

It is an arithmetic number, because the mean of its divisors is an integer number (2041676).

Almost surely, 2^21477929 is an apocalyptic number.

It is an amenable number.

21477929 is a deficient number, since it is larger than the sum of its proper divisors (3022183).

21477929 is a wasteful number, since it uses less digits than its factorization.

21477929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3748 (or 3725 counting only the distinct ones).

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

The square root of 21477929 is about 4634.4286595005. The cubic root of 21477929 is about 277.9697058237.

The spelling of 21477929 in words is "twenty-one million, four hundred seventy-seven thousand, nine hundred twenty-nine".