61655621 has 4 divisors (see below), whose sum is σ = 63644544. Its totient is φ = 59666700.

The previous prime is 61655603. The next prime is 61655623. The reversal of 61655621 is 12655616.

61655621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61655621 - 2⁶ = 61655557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61655623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 994415 + ... + 994476.

It is an arithmetic number, because the mean of its divisors is an integer number (15911136).

Almost surely, 2^61655621 is an apocalyptic number.

It is an amenable number.

61655621 is a deficient number, since it is larger than the sum of its proper divisors (1988923).

61655621 is a wasteful number, since it uses less digits than its factorization.

61655621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1988922.

The product of its digits is 10800, while the sum is 32.

The square root of 61655621 is about 7852.1093344400. The cubic root of 61655621 is about 395.0549963482.

The spelling of 61655621 in words is "sixty-one million, six hundred fifty-five thousand, six hundred twenty-one".