21404884 has 12 divisors (see below), whose sum is σ = 38329984. Its totient is φ = 10453464.

The previous prime is 21404869. The next prime is 21404899. The reversal of 21404884 is 48840412.

It is an interprime number because it is at equal distance from previous prime (21404869) and next prime (21404899).

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62052 + ... + 62395.

Almost surely, 2^21404884 is an apocalyptic number.

It is an amenable number.

21404884 is a deficient number, since it is larger than the sum of its proper divisors (16925100).

21404884 is a wasteful number, since it uses less digits than its factorization.

21404884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124494 (or 124492 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 31.

The square root of 21404884 is about 4626.5412567057. The cubic root of 21404884 is about 277.6542291220.

Subtracting 21404884 from its reverse (48840412), we obtain a triangular number (27435528 = T₇₄₀₇).

The spelling of 21404884 in words is "twenty-one million, four hundred four thousand, eight hundred eighty-four".