61291291 has 4 divisors (see below), whose sum is σ = 61508152. Its totient is φ = 61074432.

The previous prime is 61291271. The next prime is 61291303. The reversal of 61291291 is 19219216.

It is a semiprime because it is the product of two primes.

It is a 10-Lehmer number, since φ(61291291) divides (61291291-1)¹⁰.

It is a cyclic number.

It is not a de Polignac number, because 61291291 - 2⁵ = 61291259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61291271) 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, 108006 + ... + 108571.

It is an arithmetic number, because the mean of its divisors is an integer number (15377038).

Almost surely, 2^61291291 is an apocalyptic number.

61291291 is a deficient number, since it is larger than the sum of its proper divisors (216861).

61291291 is a wasteful number, since it uses less digits than its factorization.

61291291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216860.

The product of its digits is 1944, while the sum is 31.

The square root of 61291291 is about 7828.8754620316. The cubic root of 61291291 is about 394.2753171174.

The spelling of 61291291 in words is "sixty-one million, two hundred ninety-one thousand, two hundred ninety-one".