21180474 has 64 divisors (see below), whose sum is σ = 54316800. Its totient is φ = 5992704.

The previous prime is 21180463. The next prime is 21180491. The reversal of 21180474 is 47408112.

It is a super-2 number, since 2×21180474² = 897224957729352, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51582 + ... + 51990.

It is an arithmetic number, because the mean of its divisors is an integer number (848700).

Almost surely, 2^21180474 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21180474, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27158400).

21180474 is an abundant number, since it is smaller than the sum of its proper divisors (33136326).

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

21180474 is a wasteful number, since it uses less digits than its factorization.

21180474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564 (or 558 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21180474 is about 4602.2248967212. The cubic root of 21180474 is about 276.6805041385.

Adding to 21180474 its reverse (47408112), we get a palindrome (68588586).

The spelling of 21180474 in words is "twenty-one million, one hundred eighty thousand, four hundred seventy-four".