21392478 has 16 divisors (see below), whose sum is σ = 47538960. Its totient is φ = 7130808.

The previous prime is 21392467. The next prime is 21392491. The reversal of 21392478 is 87429312.

It is a super-2 number, since 2×21392478² = 915276229960968, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) 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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 198025 + ... + 198132.

It is an arithmetic number, because the mean of its divisors is an integer number (2971185).

Almost surely, 2^21392478 is an apocalyptic number.

21392478 is an abundant number, since it is smaller than the sum of its proper divisors (26146482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21392478 is a wasteful number, since it uses less digits than its factorization.

21392478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396168 (or 396162 counting only the distinct ones).

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

The square root of 21392478 is about 4625.2003199862. The cubic root of 21392478 is about 277.6005771290.

The spelling of 21392478 in words is "twenty-one million, three hundred ninety-two thousand, four hundred seventy-eight".