61667891 has 16 divisors (see below), whose sum is σ = 69141600. Its totient is φ = 54716928.

The previous prime is 61667867. The next prime is 61667909. The reversal of 61667891 is 19876616.

61667891 = T₂₃₃ + T₂₃₄ + ... + T₇₂₅.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61667891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61667821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19745 + ... + 22653.

It is an arithmetic number, because the mean of its divisors is an integer number (4321350).

Almost surely, 2^61667891 is an apocalyptic number.

61667891 is a deficient number, since it is larger than the sum of its proper divisors (7473709).

61667891 is a wasteful number, since it uses less digits than its factorization.

61667891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2998.

The product of its digits is 108864, while the sum is 44.

The square root of 61667891 is about 7852.8906142897. The cubic root of 61667891 is about 395.0812010597.

The spelling of 61667891 in words is "sixty-one million, six hundred sixty-seven thousand, eight hundred ninety-one".