61978540 has 48 divisors (see below), whose sum is σ = 141345792. Its totient is φ = 22692096.

The previous prime is 61978531. The next prime is 61978547. The reversal of 61978540 is 4587916.

It is a junction number, because it is equal to n+sod(n) for n = 61978493 and 61978502.

It is not an unprimeable number, because it can be changed into a prime (61978547) 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, 32082 + ... + 33958.

It is an arithmetic number, because the mean of its divisors is an integer number (2944704).

Almost surely, 2^61978540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61978540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70672896).

61978540 is an abundant number, since it is smaller than the sum of its proper divisors (79367252).

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

61978540 is a wasteful number, since it uses less digits than its factorization.

61978540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2026 (or 2024 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 61978540 is about 7872.6450447102. The cubic root of 61978540 is about 395.7434909920.

The spelling of 61978540 in words is "sixty-one million, nine hundred seventy-eight thousand, five hundred forty".