61821504 has 84 divisors (see below), whose sum is σ = 183360060. Its totient is φ = 19891200.

The previous prime is 61821491. The next prime is 61821521. The reversal of 61821504 is 40512816.

It can be written as a sum of positive squares in 2 ways, for example, as 28643904 + 33177600 = 5352^2 + 5760^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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, 14854 + ... + 18554.

Almost surely, 2^61821504 is an apocalyptic number.

61821504 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61821504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91680030).

61821504 is an abundant number, since it is smaller than the sum of its proper divisors (121538556).

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

61821504 is a wasteful number, since it uses less digits than its factorization.

61821504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3748 (or 3735 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 61821504 is about 7862.6651969927. The cubic root of 61821504 is about 395.4089744771.

It can be divided in two parts, 618 and 21504, that added together give a palindrome (22122).

The spelling of 61821504 in words is "sixty-one million, eight hundred twenty-one thousand, five hundred four".