21790153840 has 80 divisors (see below), whose sum is σ = 62353384128. Its totient is φ = 6896222208.

The previous prime is 21790153823. The next prime is 21790153841. The reversal of 21790153840 is 4835109712.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 21790153793 and 21790153802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21790153841) 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, 1489297 + ... + 1503856.

Almost surely, 2^21790153840 is an apocalyptic number.

21790153840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21790153840 is an abundant number, since it is smaller than the sum of its proper divisors (40563230288).

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

21790153840 is a wasteful number, since it uses less digits than its factorization.

21790153840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2993186 (or 2993180 counting only the distinct ones).

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

The spelling of 21790153840 in words is "twenty-one billion, seven hundred ninety million, one hundred fifty-three thousand, eight hundred forty".