61571640 has 128 divisors (see below), whose sum is σ = 205934400. Its totient is φ = 14622720.

The previous prime is 61571617. The next prime is 61571651. The reversal of 61571640 is 4617516.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 61571598 and 61571607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44560 + ... + 45920.

Almost surely, 2^61571640 is an apocalyptic number.

61571640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61571640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102967200).

61571640 is an abundant number, since it is smaller than the sum of its proper divisors (144362760).

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

61571640 is a wasteful number, since it uses less digits than its factorization.

61571640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417 (or 1413 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 61571640 is about 7846.7598408515. The cubic root of 61571640 is about 394.8755469700.

The spelling of 61571640 in words is "sixty-one million, five hundred seventy-one thousand, six hundred forty".