21051478 has 12 divisors (see below), whose sum is σ = 36732852. Its totient is φ = 9022020.

The previous prime is 21051473. The next prime is 21051479. The reversal of 21051478 is 87415012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051473) 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, 107308 + ... + 107503.

It is an arithmetic number, because the mean of its divisors is an integer number (3061071).

Almost surely, 2^21051478 is an apocalyptic number.

21051478 is a deficient number, since it is larger than the sum of its proper divisors (15681374).

21051478 is a wasteful number, since it uses less digits than its factorization.

21051478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214827 (or 214820 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21051478 is about 4588.1889673378. The cubic root of 21051478 is about 276.1176684432.

The spelling of 21051478 in words is "twenty-one million, fifty-one thousand, four hundred seventy-eight".