21555414 has 24 divisors (see below), whose sum is σ = 47497320. Its totient is φ = 7063008.

The previous prime is 21555407. The next prime is 21555433. The reversal of 21555414 is 41455512.

It is a super-2 number, since 2×21555414² = 929271745422792, 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 11 ways as a sum of consecutive naturals, for example, 9087 + ... + 11210.

It is an arithmetic number, because the mean of its divisors is an integer number (1979055).

Almost surely, 2^21555414 is an apocalyptic number.

21555414 is an abundant number, since it is smaller than the sum of its proper divisors (25941906).

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

21555414 is a wasteful number, since it uses less digits than its factorization.

21555414 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20364 (or 20361 counting only the distinct ones).

The product of its digits is 4000, while the sum is 27.

The square root of 21555414 is about 4642.7808477248. The cubic root of 21555414 is about 278.3035777610.

It can be divided in two parts, 2155 and 5414, that added together give a square (7569 = 87²).

The spelling of 21555414 in words is "twenty-one million, five hundred fifty-five thousand, four hundred fourteen".