55061721 has 48 divisors (see below), whose sum is σ = 96448320. Its totient is φ = 30775680.

The previous prime is 55061693. The next prime is 55061723. The reversal of 55061721 is 12716055.

It is not a de Polignac number, because 55061721 - 2⁵ = 55061689 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (55061723) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49645 + ... + 50741.

It is an arithmetic number, because the mean of its divisors is an integer number (2009340).

Almost surely, 2^55061721 is an apocalyptic number.

It is an amenable number.

55061721 is a deficient number, since it is larger than the sum of its proper divisors (41386599).

55061721 is a wasteful number, since it uses less digits than its factorization.

55061721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1143 (or 1124 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 55061721 is about 7420.3585492886. The cubic root of 55061721 is about 380.4374486712.

Adding to 55061721 its reverse (12716055), we get a palindrome (67777776).

It can be divided in two parts, 5506 and 1721, that added together give a palindrome (7227).

The spelling of 55061721 in words is "fifty-five million, sixty-one thousand, seven hundred twenty-one".