55721040 has 40 divisors (see below), whose sum is σ = 172735968. Its totient is φ = 14858880.

The previous prime is 55721033. The next prime is 55721047. The reversal of 55721040 is 4012755.

It is an interprime number because it is at equal distance from previous prime (55721033) and next prime (55721047).

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 55721040.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55721047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 115846 + ... + 116325.

Almost surely, 2^55721040 is an apocalyptic number.

It is an amenable number.

55721040 is an abundant number, since it is smaller than the sum of its proper divisors (117014928).

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

55721040 is a wasteful number, since it uses less digits than its factorization.

55721040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232187 (or 232181 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 55721040 is about 7464.6527045804. The cubic root of 55721040 is about 381.9499034293.

Adding to 55721040 its reverse (4012755), we get a palindrome (59733795).

The spelling of 55721040 in words is "fifty-five million, seven hundred twenty-one thousand, forty".