21439827 has 6 divisors (see below), whose sum is σ = 30968652. Its totient is φ = 14293212.

The previous prime is 21439823. The next prime is 21439837. The reversal of 21439827 is 72893412.

It is not a de Polignac number, because 21439827 - 2² = 21439823 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21439791 and 21439800.

It is not an unprimeable number, because it can be changed into a prime (21439823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1191093 + ... + 1191110.

It is an arithmetic number, because the mean of its divisors is an integer number (5161442).

Almost surely, 2^21439827 is an apocalyptic number.

21439827 is a deficient number, since it is larger than the sum of its proper divisors (9528825).

21439827 is a wasteful number, since it uses less digits than its factorization.

21439827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2382209 (or 2382206 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21439827 is about 4630.3160799237. The cubic root of 21439827 is about 277.8052351110.

The spelling of 21439827 in words is "twenty-one million, four hundred thirty-nine thousand, eight hundred twenty-seven".