61891533 has 20 divisors (see below), whose sum is σ = 100861728. Its totient is φ = 37509480.

The previous prime is 61891499. The next prime is 61891547. The reversal of 61891533 is 33519816.

It is a happy number.

61891533 is a `hidden beast` number, since 618 + 9 + 1 + 5 + 33 = 666.

It is not a de Polignac number, because 61891533 - 2¹⁰ = 61890509 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61891553) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 33841 + ... + 35622.

Almost surely, 2^61891533 is an apocalyptic number.

It is an amenable number.

61891533 is a deficient number, since it is larger than the sum of its proper divisors (38970195).

61891533 is a wasteful number, since it uses less digits than its factorization.

61891533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69486 (or 69477 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 61891533 is about 7867.1171975508. The cubic root of 61891533 is about 395.5582194508.

The spelling of 61891533 in words is "sixty-one million, eight hundred ninety-one thousand, five hundred thirty-three".