61566421 has 16 divisors (see below), whose sum is σ = 71392000. Its totient is φ = 52005888.

The previous prime is 61566413. The next prime is 61566433. The reversal of 61566421 is 12466516.

It is a cyclic number.

It is not a de Polignac number, because 61566421 - 2³ = 61566413 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 (61561421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 268735 + ... + 268963.

It is an arithmetic number, because the mean of its divisors is an integer number (4462000).

Almost surely, 2^61566421 is an apocalyptic number.

It is an amenable number.

61566421 is a deficient number, since it is larger than the sum of its proper divisors (9825579).

61566421 is a wasteful number, since it uses less digits than its factorization.

61566421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628.

The product of its digits is 8640, while the sum is 31.

The square root of 61566421 is about 7846.4272761557. The cubic root of 61566421 is about 394.8643897029.

The spelling of 61566421 in words is "sixty-one million, five hundred sixty-six thousand, four hundred twenty-one".