61945681 has 16 divisors (see below), whose sum is σ = 75222400. Its totient is φ = 49828608.

The previous prime is 61945679. The next prime is 61945699. The reversal of 61945681 is 18654916.

It is a cyclic number.

It is not a de Polignac number, because 61945681 - 2¹ = 61945679 is a prime.

It is a super-2 number, since 2×61945681² = 7674534789107522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61945661) 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, 12361 + ... + 16633.

It is an arithmetic number, because the mean of its divisors is an integer number (4701400).

Almost surely, 2^61945681 is an apocalyptic number.

It is an amenable number.

61945681 is a deficient number, since it is larger than the sum of its proper divisors (13276719).

61945681 is a wasteful number, since it uses less digits than its factorization.

61945681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4408.

The product of its digits is 51840, while the sum is 40.

The square root of 61945681 is about 7870.5578582461. The cubic root of 61945681 is about 395.6735418660.

It can be divided in two parts, 61945 and 681, that added together give a palindrome (62626).

The spelling of 61945681 in words is "sixty-one million, nine hundred forty-five thousand, six hundred eighty-one".