21178962780 has 48 divisors (see below), whose sum is σ = 62789398560. Its totient is φ = 5315504128.

The previous prime is 21178962767. The next prime is 21178962793. The reversal of 21178962780 is 8726987112.

It is an interprime number because it is at equal distance from previous prime (21178962767) and next prime (21178962793).

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10380825 + ... + 10382864.

It is an arithmetic number, because the mean of its divisors is an integer number (1308112470).

Almost surely, 2^21178962780 is an apocalyptic number.

21178962780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21178962780 is an abundant number, since it is smaller than the sum of its proper divisors (41610435780).

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

21178962780 is a wasteful number, since it uses less digits than its factorization.

21178962780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20763718 (or 20763716 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 51.

The spelling of 21178962780 in words is "twenty-one billion, one hundred seventy-eight million, nine hundred sixty-two thousand, seven hundred eighty".