31261920 has 48 divisors (see below), whose sum is σ = 98476560. Its totient is φ = 8336384.

The previous prime is 31261907. The next prime is 31261921. The reversal of 31261920 is 2916213.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31261921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32085 + ... + 33044.

It is an arithmetic number, because the mean of its divisors is an integer number (2051595).

Almost surely, 2^31261920 is an apocalyptic number.

31261920 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31261920 is an abundant number, since it is smaller than the sum of its proper divisors (67214640).

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

31261920 is a wasteful number, since it uses less digits than its factorization.

31261920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65147 (or 65139 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 31261920 is about 5591.2359993118. The cubic root of 31261920 is about 315.0203060732.

The spelling of 31261920 in words is "thirty-one million, two hundred sixty-one thousand, nine hundred twenty".