61215553 has 16 divisors (see below), whose sum is σ = 71740800. Its totient is φ = 52212048.

The previous prime is 61215541. The next prime is 61215577. The reversal of 61215553 is 35551216.

It is not a de Polignac number, because 61215553 - 2⁹ = 61215041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61215533) 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 15 ways as a sum of consecutive naturals, for example, 108450 + ... + 109012.

It is an arithmetic number, because the mean of its divisors is an integer number (4483800).

Almost surely, 2^61215553 is an apocalyptic number.

It is an amenable number.

61215553 is a deficient number, since it is larger than the sum of its proper divisors (10525247).

61215553 is an equidigital number, since it uses as much as digits as its factorization.

61215553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901 (or 887 counting only the distinct ones).

The product of its digits is 4500, while the sum is 28.

The square root of 61215553 is about 7824.0368736350. The cubic root of 61215553 is about 394.1128474201.

Adding to 61215553 its reverse (35551216), we get a palindrome (96766769).

The spelling of 61215553 in words is "sixty-one million, two hundred fifteen thousand, five hundred fifty-three".