61861780 has 24 divisors (see below), whose sum is σ = 133422408. Its totient is φ = 24075648.

The previous prime is 61861769. The next prime is 61861781. The reversal of 61861780 is 8716816.

It can be written as a sum of positive squares in 4 ways, for example, as 17825284 + 44036496 = 4222^2 + 6636^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61861781) 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, 41059 + ... + 42538.

It is an arithmetic number, because the mean of its divisors is an integer number (5559267).

Almost surely, 2^61861780 is an apocalyptic number.

It is an amenable number.

61861780 is an abundant number, since it is smaller than the sum of its proper divisors (71560628).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61861780 is a wasteful number, since it uses less digits than its factorization.

61861780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83643 (or 83641 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 61861780 is about 7865.2259980245. The cubic root of 61861780 is about 395.4948239720.

The spelling of 61861780 in words is "sixty-one million, eight hundred sixty-one thousand, seven hundred eighty".