61501781 has 8 divisors (see below), whose sum is σ = 67721184. Its totient is φ = 55387120.

The previous prime is 61501753. The next prime is 61501789. The reversal of 61501781 is 18710516.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61501781 - 2⁶ = 61501717 is a prime.

It is a super-2 number, since 2×61501781² = 7564938132343922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61501789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24950 + ... + 27303.

It is an arithmetic number, because the mean of its divisors is an integer number (8465148).

Almost surely, 2^61501781 is an apocalyptic number.

It is an amenable number.

61501781 is a deficient number, since it is larger than the sum of its proper divisors (6219403).

61501781 is a wasteful number, since it uses less digits than its factorization.

61501781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52371.

The product of its (nonzero) digits is 1680, while the sum is 29.

The square root of 61501781 is about 7842.3071222696. The cubic root of 61501781 is about 394.7261489124.

The spelling of 61501781 in words is "sixty-one million, five hundred one thousand, seven hundred eighty-one".