61501440 has 416 divisors, whose sum is σ = 264208896. Its totient is φ = 11796480.

The previous prime is 61501417. The next prime is 61501457. The reversal of 61501440 is 4410516.

61501440 = T₁₃₄₃ + T₁₃₄₄ + ... + T₁₄₀₇.

It is a tau number, because it is divible by the number of its divisors (416).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 520 × 264 × 448.

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, 4730874 + ... + 4730886.

Almost surely, 2^61501440 is an apocalyptic number.

61501440 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 61501440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132104448).

61501440 is an abundant number, since it is smaller than the sum of its proper divisors (202707456).

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

61501440 is a wasteful number, since it uses less digits than its factorization.

61501440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 61501440 is about 7842.2853811883. The cubic root of 61501440 is about 394.7254193841.

Adding to 61501440 its reverse (4410516), we get a palindrome (65911956).

It can be divided in two parts, 61 and 501440, that added together give a triangular number (501501 = T₁₀₀₁).

The spelling of 61501440 in words is "sixty-one million, five hundred one thousand, four hundred forty".