61551 has 12 divisors (see below), whose sum is σ = 101712. Its totient is φ = 35136.

The previous prime is 61547. The next prime is 61553. The reversal of 61551 is 15516.

61551 is a `hidden beast` number, since 615 + 51 = 666.

It is not a de Polignac number, because 61551 - 2² = 61547 is a prime.

61551 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61553) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 426 + ... + 551.

It is an arithmetic number, because the mean of its divisors is an integer number (8476).

2⁶¹⁵⁵¹ is an apocalyptic number.

61551 is a deficient number, since it is larger than the sum of its proper divisors (40161).

61551 is a wasteful number, since it uses less digits than its factorization.

61551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 990 (or 987 counting only the distinct ones).

The product of its digits is 150, while the sum is 18.

The square root of 61551 is about 248.0947399684. The cubic root of 61551 is about 39.4831418742.

It can be divided in two parts, 615 and 51, that added together give a palindrome (666).

The spelling of 61551 in words is "sixty-one thousand, five hundred fifty-one".