21557034 has 48 divisors (see below), whose sum is σ = 49182120. Its totient is φ = 6814080.

The previous prime is 21557033. The next prime is 21557047. The reversal of 21557034 is 43075512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 19316025 + 2241009 = 4395^2 + 1497^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21556989 and 21557007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21557033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31504 + ... + 32180.

Almost surely, 2^21557034 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21557034, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24591060).

21557034 is an abundant number, since it is smaller than the sum of its proper divisors (27625086).

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

21557034 is a wasteful number, since it uses less digits than its factorization.

21557034 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775 (or 772 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 21557034 is about 4642.9553088523. The cubic root of 21557034 is about 278.3105495671.

The spelling of 21557034 in words is "twenty-one million, five hundred fifty-seven thousand, thirty-four".