21677418 has 48 divisors (see below), whose sum is σ = 54939456. Its totient is φ = 6048000.

The previous prime is 21677407. The next prime is 21677443. The reversal of 21677418 is 81477612.

It is a super-2 number, since 2×21677418² = 939820902293448, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3418 + ... + 7418.

It is an arithmetic number, because the mean of its divisors is an integer number (1144572).

Almost surely, 2^21677418 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21677418, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27469728).

21677418 is an abundant number, since it is smaller than the sum of its proper divisors (33262038).

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

21677418 is a wasteful number, since it uses less digits than its factorization.

21677418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4059 (or 4056 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 21677418 is about 4655.9014164821. The cubic root of 21677418 is about 278.8276578525.

The spelling of 21677418 in words is "twenty-one million, six hundred seventy-seven thousand, four hundred eighteen".