61643421 has 36 divisors (see below), whose sum is σ = 104578812. Its totient is φ = 34884864.

The previous prime is 61643401. The next prime is 61643423. The reversal of 61643421 is 12434616.

61643421 is a `hidden beast` number, since 616 + 4 + 3 + 42 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 19263321 + 42380100 = 4389^2 + 6510^2 .

It is not a de Polignac number, because 61643421 - 2⁹ = 61642909 is a prime.

It is a super-2 number, since 2×61643421² = 7599822705166482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61643423) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 49215 + ... + 50451.

It is an arithmetic number, because the mean of its divisors is an integer number (2904967).

Almost surely, 2^61643421 is an apocalyptic number.

It is an amenable number.

61643421 is a deficient number, since it is larger than the sum of its proper divisors (42935391).

61643421 is a wasteful number, since it uses less digits than its factorization.

61643421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1370 (or 1360 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 61643421 is about 7851.3324346890. The cubic root of 61643421 is about 395.0289376866.

The spelling of 61643421 in words is "sixty-one million, six hundred forty-three thousand, four hundred twenty-one".