21210678 has 12 divisors (see below), whose sum is σ = 45956508. Its totient is φ = 7070220.

The previous prime is 21210649. The next prime is 21210691. The reversal of 21210678 is 87601212.

It is a super-2 number, since 2×21210678² = 899785722439368, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 589168 + ... + 589203.

It is an arithmetic number, because the mean of its divisors is an integer number (3829709).

Almost surely, 2^21210678 is an apocalyptic number.

21210678 is an abundant number, since it is smaller than the sum of its proper divisors (24745830).

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

21210678 is a wasteful number, since it uses less digits than its factorization.

21210678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1178379 (or 1178376 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 21210678 is about 4605.5051840162. The cubic root of 21210678 is about 276.8119599424.

The spelling of 21210678 in words is "twenty-one million, two hundred ten thousand, six hundred seventy-eight".