61221655 has 32 divisors (see below), whose sum is σ = 82487808. Its totient is φ = 43248000.

The previous prime is 61221649. The next prime is 61221701. The reversal of 61221655 is 55612216.

It is not a de Polignac number, because 61221655 - 2¹¹ = 61219607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 572112 + ... + 572218.

It is an arithmetic number, because the mean of its divisors is an integer number (2577744).

Almost surely, 2^61221655 is an apocalyptic number.

61221655 is a deficient number, since it is larger than the sum of its proper divisors (21266153).

61221655 is a wasteful number, since it uses less digits than its factorization.

61221655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327.

The product of its digits is 3600, while the sum is 28.

The square root of 61221655 is about 7824.4268160677. The cubic root of 61221655 is about 394.1259421135.

It can be divided in two parts, 6122 and 1655, that added together give a palindrome (7777).

The spelling of 61221655 in words is "sixty-one million, two hundred twenty-one thousand, six hundred fifty-five".