21485478 has 16 divisors (see below), whose sum is σ = 49109760. Its totient is φ = 6138696.

The previous prime is 21485437. The next prime is 21485489. The reversal of 21485478 is 87458412.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 255738 + ... + 255821.

It is an arithmetic number, because the mean of its divisors is an integer number (3069360).

Almost surely, 2^21485478 is an apocalyptic number.

21485478 is an abundant number, since it is smaller than the sum of its proper divisors (27624282).

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

21485478 is a wasteful number, since it uses less digits than its factorization.

21485478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511571.

The product of its digits is 71680, while the sum is 39.

The square root of 21485478 is about 4635.2430356994. The cubic root of 21485478 is about 278.0022686701.

It can be divided in two parts, 2148 and 5478, that added together give a triangular number (7626 = T₁₂₃).

The spelling of 21485478 in words is "twenty-one million, four hundred eighty-five thousand, four hundred seventy-eight".