61299781 has 4 divisors (see below), whose sum is σ = 61516672. Its totient is φ = 61082892.

The previous prime is 61299769. The next prime is 61299793. The reversal of 61299781 is 18799216.

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 an interprime number because it is at equal distance from previous prime (61299769) and next prime (61299793).

It is a cyclic number.

It is not a de Polignac number, because 61299781 - 2⁷ = 61299653 is a prime.

It is a super-2 number, since 2×61299781² = 7515326301295922, 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 (61299701) 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, 108021 + ... + 108586.

It is an arithmetic number, because the mean of its divisors is an integer number (15379168).

Almost surely, 2^61299781 is an apocalyptic number.

It is an amenable number.

61299781 is a deficient number, since it is larger than the sum of its proper divisors (216891).

61299781 is a wasteful number, since it uses less digits than its factorization.

61299781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216890.

The product of its digits is 54432, while the sum is 43.

The square root of 61299781 is about 7829.4176667234. The cubic root of 61299781 is about 394.2935211332.

The spelling of 61299781 in words is "sixty-one million, two hundred ninety-nine thousand, seven hundred eighty-one".