61691081 has 4 divisors (see below), whose sum is σ = 64938000. Its totient is φ = 58444164.

The previous prime is 61691029. The next prime is 61691087. The reversal of 61691081 is 18019616.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61691081 - 2⁶ = 61691017 is a prime.

It is a super-2 number, since 2×61691081² = 7611578949897122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61691087) 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, 1623431 + ... + 1623468.

It is an arithmetic number, because the mean of its divisors is an integer number (16234500).

Almost surely, 2^61691081 is an apocalyptic number.

It is an amenable number.

61691081 is a deficient number, since it is larger than the sum of its proper divisors (3246919).

61691081 is a wasteful number, since it uses less digits than its factorization.

61691081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3246918.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 61691081 is about 7854.3670018659. The cubic root of 61691081 is about 395.1307178326.

The spelling of 61691081 in words is "sixty-one million, six hundred ninety-one thousand, eighty-one".