31497840 has 240 divisors, whose sum is σ = 119429856. Its totient is φ = 7372800.

The previous prime is 31497827. The next prime is 31497859. The reversal of 31497840 is 4879413.

31497840 = T₃₀₄ + T₃₀₅ + ... + T₆₀₀.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×31497840² = 1984227849331200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 31497795 and 31497804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 324672 + ... + 324768.

Almost surely, 2^31497840 is an apocalyptic number.

31497840 is a gapful number since it is divisible by the number (30) 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 31497840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59714928).

31497840 is an abundant number, since it is smaller than the sum of its proper divisors (87932016).

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

31497840 is a wasteful number, since it uses less digits than its factorization.

31497840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 31497840 is about 5612.2936487679. The cubic root of 31497840 is about 315.8107610211.

The spelling of 31497840 in words is "thirty-one million, four hundred ninety-seven thousand, eight hundred forty".