61555421 has 4 divisors (see below), whose sum is σ = 64795200. Its totient is φ = 58315644.

The previous prime is 61555411. The next prime is 61555423. The reversal of 61555421 is 12455516.

It is a happy number.

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 61555421 - 2¹⁸ = 61293277 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 (61555423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1619861 + ... + 1619898.

It is an arithmetic number, because the mean of its divisors is an integer number (16198800).

Almost surely, 2^61555421 is an apocalyptic number.

It is an amenable number.

61555421 is a deficient number, since it is larger than the sum of its proper divisors (3239779).

61555421 is a wasteful number, since it uses less digits than its factorization.

61555421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3239778.

The product of its digits is 6000, while the sum is 29.

The square root of 61555421 is about 7845.7262888786. The cubic root of 61555421 is about 394.8408716502.

The spelling of 61555421 in words is "sixty-one million, five hundred fifty-five thousand, four hundred twenty-one".